(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Chinese]SZ[19]KM[7.50]
PW[alphago master]PB[alphago master]C[2017 12 20


up to 32:36
up to 42:49 rough translation
rapid translation up to 1:22:.//
very interesting discussion 1:33:55

Translated by Daniel Hu 5d

Liu Xing 7p
Chang Hao 9p
Fan Hui 2p

(...  between paragraphs denotes time they spent talking in the variations so see those for my translation. Most of the time they talk in order, but not always. When they return to the main branch, so does my translation)

"Just one line change can often mean the difference between thick and thin"

Liu: Today we are doing an unusual review of a game from the future

Fan Hui is Deepmind's weiqi ambassador and will be giving a detailed commentary.

Chang Hao world champion, everyone knows. He also attended the Wuzhen summit and has seen some of the 50 self-play games, tell us your thoughts.

Chang: Alphago has truly changed the way we think about go. You call it games from the future. And truly, it is overturning many of the ideas we learnt when we were young.

Of course, it is very strong, and demonstrated that with results at Wuzhen, and maybe it does show future trends. But for professional go players, it is more that it has given us a new way of thinking. Though personally, I may not copy many of its moves and ideas, as many of them we still can't understand.

But it has opened our eyes. And there was the conference on the 26th, with Mr Hassabis saying how alphago's appearance isn't a conflict, it is more a tool, that we can use to explore more of the magic of go. I think these words were very appropriate, and I feel the same.

It is less about matches against it, and more, well go is just too hard, even though human go has developed for several thousand years, with practically no change in the rules, we still know so little. Many great masters have said this. But after alphago, there is a lot we can borrow, letting our thinking look further ahead. I think this is very important to us professional players, that is, on the competitive side.

Liu: I think Chang summed it up very well, telling the feelings of the large majority of pros. It is like we are starting to learn anew.

Fan: This is what we want. For alphago to be used as a tool. It can really help us explore.

Liu: I think we are very lucky to live in this era.

Chang: And we can see how young players in competitions are slowly starting to try out alphago's moves. Though I think this will be a very long process, where we slowly understand, digest, and analyse and work out in what context we play certain moves.

Because many of alphago's moves and variations are not entirely new, it is just that we have played them in different surrounding board positions. It is just that through alphago's data and understanding, it has modified the way you play them. These have all given us inspiration.

Liu/Fan: without further ado, let's start



]
;B[pd]
;W[dp]C[Liu: we don't need to ask which side is which this time

(laughter)]
;B[pq]
;W[dd]
;B[ql]C[Chang: Actually, these 50 games really made me think of Master Wu Qingyuan (Go Seigen). 

Many probably know that after the car accident, his competitive go declined and very rarely played formally. But his love of, well you can't call it love. He was fully integrated with go.

Liu: with his life

Chang: so every day he would play go with himself. This is very hard to keep up. For us, it would be very hard with no match coming up, and knowing in all likelihood there would never be a match coming up.

And his reactions were fast. When discussing with us, often we would take a while to consider, and he would be impatient, putting the stones down for us, and telling us the quality of the moves.

Whereas we would still be thinking, he would already be telling us B should play here, and then W should play here, and so on, often playing out a dozen moves.

When looking at the alphago self-play, I was reminded of the feeling of playing go with Master Wu 20 years ago.

Liu: As many go players have noticed, there are quite a few similarities between Master Wu's ideas and alphago.

Fan: Quite a few ideas, Master Wu mentioned a long time ago such as how this should and shouldn't be played.

Chang: Actually, less so in the self-play, but more so in the Master series.

Such as it never plays the small knight's move enclosure from the 3-4 (especially with black)

 (see variation for long talk on Go Seigen)]
(;W[qf]C[Fan: this is a mini-chinese opening]
(;B[nc]TR[fc][nc][qe]C[liu: chang?

chang: a bit surprised, because

...

fan: actually, alphago does play different moves in the same positions, it doesn't have an absolute move. Sometimes it will play R15, sometimes F17 or O17. Nothing is certain.

Chang: So up to move 6, it has a selection of moves. Are the winning probabilities all pretty much the same?

If today it's happy it will kick, tomorrow, is it like this?

Fan: Yes. Especially in the opening, it is very unlikely that one move is the only move.

Chang: This is similar to how humans think. In the opening, everything is relative, it isn't that there is only one move and if you don't play it, then your winning chance drops dramatically.

Liu: In the opening, on the one hand you may play favourites, on the other it is style

Fan: or whether you are in form

Liu: but this small knight's

Chang: it is still a bit surprising. Because it seems that whether you play the Chinese opening or this, if W enters from the inside, B has to pressure W a bit, whether it is the kick or something. You need to attack, or at least have some plans.

Fan: to give it some pressure

Chang: because I already have a helping stone (R8), so I shouldn't let you easily settle here.

This is the sort of theory we were taught when younger, or what we've learnt from experience.

Fan: I find that alphago, just from my experience, it's not necessarily correct, it always plays good direction. Wherever is wide and open it will play there.

Chang: it isn't so concerned with local profit and loss

Fan: yes, normally, as long as you play towards an open area, it can't be too bad a move.

Liu: efficiency

Fan: perhaps it thinks that stone efficiency is more important.
]
(;W[qd]C[Chang: it tends to like attaching, and very rarely the small knight's

Fan: I used to think this was only a handicap game joseki

Chang: or a sabaki move. Normally it is played if B has extra pincer support.

...

Chang: it is played when W doesn't have enough space to make a base and is under attack. That is what we were taught when we were younger.

...

Chang: its thinking isn't the same as humans

Chang: it seems that it will play the attach anytime, if it has nothing better to do.

Fan: in this shape, it always seems to attach and double hane. There isn't another move.]
(;B[qc]C[Fan: so in the game, it attaches, not letting B play 3-3.
]
;W[rc]C[Chang: maybe it thinks like: either I don't what you to take sente easily, or I want you to settle the shape.]
(;B[qe]C[...

Chang: and if B plays here, maybe W will have a chance to take sente, or it is a different game.

Fan: It's not impossible [that alphago thinks like that\]

And depending on the context, through analysing the efficiency of stones, maybe it just thinks this method is good.]
;W[rd]
;B[re]C[Chang: this is a joseki]
;W[pe]C[Liu: standard shape

Chang: it has returned to standard shapes.]
;B[rf]
;W[pc]C[Fan: I learnt this as a kid too]
;B[od]
;W[pb]C[Chang: W lives]
;B[qg]C[Liu: it comes to the end of this part

Fan: not yet in its eyes]
(;W[md]
(;B[of]C[Fan: it makes an exchange

Chang: for humans,

Liu: a bit dissatisfied?

Chang: we would first preserve the aji

...

Fan: I think the exchange may be connected to the upcoming variation as one sequence.

Fan: since there is still the possibility of connecting out to fight]
;W[pp]TR[op][qp][oq][qq]C[Fan: another of its signature moves

Chang: classic alphago

Fan: perhaps the exchange is ...

Chang: yes, it thinks that after this attachment, B may get thick and W won't be able to make the N16 for P14 (profitable) exchange. So W may as well make the exchange now, in that case.

...

Chang: actually this move was first played by Takemiya Masaki.

... (all the way up to move 30)

Liu: are there any other options?]
(;B[qp]C[...

]
;W[oq]
;B[po]
;W[op]
;B[qq]
;W[oo]
;B[pn]
;W[kq]C[Chang: this variation was around in Takemiya's era, only the Q4 squeeze loses points

... 

Liu: So Chang, right now, do you prefer W or B.

Chang: Truly it is difficult. B has solid territory. If you asked Kitani sensei, perhaps he would certainly have liked B.

With territory right now

Liu: very solid

Chang: so solid you can't break it, and maybe you can break the R10 points, but, I mean!

At least the 3rd line territory (i.e. 2 lines each) you basically can't remove, it is too sturdy.

But W is faster, with stones on the outside, while B has all its stones on one side of the board.

It is quite hard to choose, and it's a matter of style.

Style is also a matter of what you are good at. Those who like the outside, who like W, may think they are stronger at dealing with that.

Fan: So Takemiya probably wouldn't choose B, and Cho Chikun probably wouldn't choose W.

Chang: Or Kobayashi would just say B has tangible material.

]
(;B[cq]C[Fan: actually a lot of the time alphago just plays signature moves.

Chang: In the self-play games, was there even any game without a 3-3 invasion?

Liu: those with 4 3-4s

Chang: well, pretty much every game had a 3-3 invasion.

Fan: In nirensei, there is practically always a 3-3 invasion. Only in particular surroundings, such as the 3-4, high approach attach underneath joseki are there approaches instead of 3-3 invasions.]
;W[dq]
;B[cp]
;W[co]
;B[bo]
;W[bn]
;B[cn]
;W[do]
;B[bm]
;W[bp]
;B[an]
;W[bq]
;B[cf]
(;W[em]C[Chang, Liu: all normal

Chang: Its signature move is to tenuki an approach to a 4-4. Before we would tenuki an approach to 3-4, but with 4-4, we would defend, pincer or kick, being scared of the double approach.

Fan: I was taught that after a double approach, if you kosumi and they take 3-3, you've already lost out.

Liu: This is overturning our previous understanding.

Chang: Especially here when the top side is spacious and B has some thickness (in the upper right), W would normally answer the approach, as after B's double approach, it will work well with the thickness, like a chemical reaction.

For us, responding to the approach is more likely. But this knight's move is also very big.]
;B[fc]C[Chang: B has to double approach]
;W[df]
;B[dg]
;W[ef]
(;B[cd]C[Fan: it seems that in this shape, it attaches most of the time.

Chang: this is very popular these days.]
(;W[cc]
;B[ce]
(;W[dc]C[Liu: I think that in human games, normally only if W has pincered black will we play D17.

Chang: The connection has an attitude of attacking B.


...

so our theory was that if W is the defender, W should tiger, and if W is aggressor W should connect. But alphago always connects either way.

...

Chang: before, when double approached, W would always tiger here.

Fan: and this was also played in the team game vs alphago

Chang: it always connects]
(;B[id]
(;W[gd]
(;B[gc]C[Liu: later, W can play F16 to defend the cutting point

Chang: this point is a good shape]
;W[di]C[Fan: W didn't defend yet

]
;B[eg]C[Chang: It plays the order very well.]
(;W[fd]C[Fan: very professional]
;B[hd]
;W[ib]C[Liu: still very professional]
;B[hb]
;W[fg]C[...

Liu: often this hane at the head of two stones feels very severe]
(;B[fh]C[Chang: it's turned into middlegame fighting

]
(;W[gh]C[...

Fan: so the cut is taking a very big risk. and in the game W chose a more gentle variation.]
;B[fi]
(;W[ic]C[first this exchange

(long divergence on alphago's time usage)]
;B[hc]
;W[cl]C[Liu: it feels like W's moves are very lively, especially its move order

Chang: playing in one area, then another,

Fan: here and there

Chang: it looks like the moves of a strong player]
;B[ch]
;W[ci]
(;B[dl]C[Fan: "excuse me" (dropped a stone)

Liu: B's meaning now is that B has a cutting point (E12) but no time to defend it.

...

Fan: so it looks like B is really in trouble so 

Chang: good move! that's the first instinct
]
(;W[dk]C[...

Fan: so it plays here

Chang: because it is playing against itself, it knows what it is trying to do]
;B[el]
(;W[eh]
;B[ek]
;W[bh]
;B[bg]
;W[bi]C[Fan: so W starts to play semeai with this group

Chang, Liu: swapping the group to semeai with.]
;B[bl]
;W[bd]
;B[be]
;W[ad]
(;B[af]C[Chang: only move]
;W[bk]
;B[ej]
;W[ck]
(;B[cm]
;W[aj]
;B[ah]C[Chang: so it turns into seki

Liu: both sides have a very similar shape.]
;W[mc]C[Chang: in this seki, W does have some profit as the top left corner is completely alive now, and even, the D15 connection has sente aji.

Of course, B doesn't have to respond, but afterwards, W will have the option to play ko or seki.

So this will have some relevance if B cuts at F14. However much or little.]
;B[gg]C[Fan: so that is why B chooses this cut.]
;W[ff]
;B[hg]C[Chang: yes that makes sense.

Liu: this way, at least, W's B16 and A16 have value

Chang: I'm already alive]
;W[kc]C[Fan: should we make a positional judgement?

Liu: well, B's right side is pretty solid territory, Chang, how do we count?

Chang: normally if we count all the 3rd line territory, then it's around 35 points on the right, then at least 40 points with some potential in the centre.

Fan: if we count the two W groups on the top right together

Chang: that's about 10 points

Liu: then including the top left, all 3 groups make around 20.

Chang: the lower left is 10 points

Liu: so B has 40 points with some potential and thickness in the centre, and W has 30 points added to the lower side.

Chang: B's thickness is a bit subtle, as there is a cut at D7 and there is aji with the G12 stone to profit or escape.

Fan: but B feels like it is solid everywhere, not just the centre wall, but also the whole of the right side.

Chang: but this sort of thickness, we can easily overestimate. Why? Because we've already counted the 3rd line territory for B.

And if W is thick, then we've counted too much on the right.

Or in other words, even just counting the right side to be B's territory, 

...

Chang: therefore, if you count B as thick, then you can't count the right side points, but since we've already counted points on the right side, we can no longer count B as think.

Fan: this game is very hard to make a judgement.

We have a rough estimate of points, but there are still so many uncertainties to come.

Chang: the feeling is that this game is still in a balance.

Liu: A-sensei's judgement should be that this is still even?

Fan: yes, normally at this stage, it will consider the game even.

Liu: both are top-level players

Chang: I have a question. Is it that the sum of the B's win probability and W's win probability always sum to 100%?

Fan: it should be like this

Chang: is it impossible to be like: W thinks it has 55% win chance, and B also thinks it has 55% win chance. Is this possible?

Fan: This won't happen. The two have exactly the same ways of thinking, they are exactly the same. And there is nothing like: today it is feeling good, another day it is tired, nothing like this.

Chang: In other words, if one side thinks the probability is 52%, the other side must think their probability is 48%.]
(;B[mq]C[Liu: B hears what we've said.
if B turns the lower side into zero points, then it has 10 more points on the board, and the game is good.

This invasion, I feel like it is also trying to show where the Q4 exchange loses something.

Chang: because W loses a liberty.

Fan: W had an interesting response]
(;W[lo]C[Fan: so that may be why in the game, it plays here

Liu: a light floating feeling]
;B[mr]
(;W[fm]C[Fan: in the game W extends. very interesting]
(;B[dj]C[...

Fan: in the game B actually first pushed, then connected

...

Fan: so pushing wasn't just a random move!

Chang: perhaps alphago is still getting stronger. Before, it used to play sente exchanges randomly, where it wasn't necessary. We thought that it might just be simplify the game, cutting down variations. But in later versions, its precision is increasing. Here if you don't push, W has a direct ko, but after the push, though W can still play ko, it is a bad one step ko.]
;W[cj]
;B[dm]C[Chang: yes, because if B is going to connect, pushing first is a necessary move order.

Because theoretically W can still play ko to kill B]
(;W[nm]
;B[or]
;W[jh]C[Fan. W plays this interesting move

(see variations for very lengthy discussion)

...

Liu: we all know that in the latter half of the game, the thick and thinness of both sides is critical, but how to make your own groups thick and your opponents' groups thin

Fan: and how to make exchanges, and turn these into real profit

Liu: how to take advantage of the opponents' weaknesses and turn them into something I can use.

Fan: this is very hard, and truly very subtle.

this move is really very interesting

Liu: A feeling for where to play in the centre, how to make a judgement, and choose a direction, whether from alphago master or ..., they all give us a large boost, and a lot to learn from.

Chang: It is hard for humans to have a sense of the centre. It is more based on a feeling, and hard to put numbers to it. 

But like Liu said, we've had many games from since when we didn't understand alphago. After over 100 games, we do have more understanding.

Firstly, it has given us a lot of new theories on the opening, and an open mindedness, and secondly it gives us a lot on the centre, when it is feeling, or increased respect. It places more importance on the centre.

Liu: it should give us a lot to learn from.

Fan: after I analysed these variations, the more I looked at this move, the more it seemed meaningful.

and why it eventually chose to come out from the other direction at L14

Chang: but Fan sensei, can I ask if it still thought this position was still even?

Fan: yes, it still thinks it is even. Very very even.

Chang: oh, I thought that at this point, W's winning percentage was already slowly climbing.]
(;B[qb]C[Liu: this gains if W tries to connect underneath.

Chang: this is interesting

...

Chang: perhaps in fighting at the top, it is important, as in later fighting, this may no longer be sente.

Liu: we don't know what will happen then.

Chang: it isn't absolute sente

but

...

Chang: actually one point difference to pros is quite painful.

at least when the game situation isn't clear yet ...

Liu: for alphago 1 point is even more painful, equal to 2 games.

Fan: it's probably because in the following fighting B foresaw that W was going to connect underneath, and hence that this move would profit.

Chang: so this sort of position is something that can give humans a lot of grief. It comes to this point and we have to decide whether or not to make this exchange. We would be quite indecisive.

We might be under pressure to make a choice, but it is a struggle.]
;W[rb]
(;B[kf]C[Fan: B played a very strange move, not connecting up but playing over here!

Chang: maybe it is a plan from D7?

Fan: maybe

...

Chang: This move looks like a desperate move, only played when definitely behind!

... (very long and interesting discussion on J11)]
;W[mh]C[Fan: W plays a nice looking shape

Chang: yes as O15 is half-sente, but it doesn't play it first.

Liu: the connection from L14 to P14 looks weird.]
;B[lg]C[Fan: B just connects up blindly!]
;W[lh]
;B[ne]C[Liu: it looks very strange

Fan: these 3 moves seem so strange!

Chang: This should be a difference to the way humans think

Top professionals wouldn't play like this

...

Fan: And white still doesn't want to connect underneath!

if it thought it was ahead, maybe W would just connect, given that the centre moves have profited

Liu: at least the 3 W moves for 3 B moves seem to be outside for inside exchanges.]
(;W[ig]C[Fan: so in the game, W still refuses to connect under

Chang: so if the W centre really becomes thickness and you can't push and cut, then W will win.]
;B[kd]C[Liu: forcing W to connect under

Fan: still not]
;W[me]
(;B[oc]C[Fan: so finally B can't endure anymore

Chang: because perhaps just the difference with the O13 sente is the difference between whether B can cut or not.

Fan: if we were just looking at the moves without this discussion, we would have no idea what the two players were fighting over!

every move has it's meaning.]
;W[mf]
;B[mg]
;W[ng]
(;B[if]
;W[nf]
;B[nh]
;W[og]
;B[ni]
;W[kg]
;B[lf]
;W[hh]
;B[hf]C[Chang: it feels like W has the advantage in the fight

Fan: when I was looking at it, it seemed a complete mess -  so many big groups not alive. And even after A8, the B group doesn't just live that easily.

It's is super huge dragon - if C6 dies, then C12 dies!

So suddenly there are 5 large groups not alive.

Chang: because for W, the Q18 corner may be sacrificeable, if the N17 needs to live, it can.

And also W is moving into B's right side territory, so if B can't hold W in, then B may have a problem with territory.

Actually, from the current perspective, the D10 C10 exchange may have been bad for black. But at the time, if B didn't push, it might not have the opportunity to, and W's play may change, as W reserves the option to start the ko with A11.

But from a purely perfect perspective, could B have delayed pushing until the last moment, as W probably wouldn't start the ko yet. But this is just in theory, as it practice it is too hard to manage.

In the old Japanese culture, they didn't just treat go as competitive, but also as art, even if it didn't mean playing the technically best moves.

For example, in the alphago - Lee Sedol game 2. When it played the tiger mouth and peeped and tenukied.

From an artistic perspective, when it peeps now it can get a response. When it peeps later, it can probably also get the same response. So could it delay peeping until the last possible moment?]
(;W[oj]C[W has to come out here, this is the communication line, and line to fight over for victory or defeat

if W can't play here, the whole previous variation just doesn't work for W.]
;B[cr]
;W[br]
;B[nj]
;W[nk]
;B[mk]
;W[oi]
;B[lj]
;W[ij]C[Fan: now at least 6 dragons, all a mess and unclear.

Liu: The only certain lifes are W's top left corner and B's lower right corner.

Chang: there is a lot of subtlety to this position.]
;B[il]C[Fan: from here, W's winning percentage starts to climb.

Chang: it is a big difference that B couldn't get A8 in sente.]
;W[hl]
;B[im]
;W[ik]
(;B[kl]
;W[ml]
;B[ok]
;W[nl]
;B[oh]
;W[pg]
;B[pf]
;W[ph]
;B[kj]
(;W[qj]C[this W group is much safer now, and W can pretty much get S12 in sente.

as B only has a ko for an eye at the top, and it is such a flower ko.]
;B[hm]
;W[jl]C[Fan: W suddenly fights

Chang: oyo! that's aggressive!

directly using B's shortage of liberties]
;B[jm]
;W[jk]
;B[ll]
;W[km]C[one group turns into 2 and neither has many liberties]
;B[lm]
;W[kn]C[B only has 2 liberties so has to escape]
;B[mn]C[W can't stop B connecting]
(;W[gl]
;B[ip]C[nothing is clear anymore, these B stones aren't alive, but neither are the W stones]
(;W[al]C[Liu: that seems very aggressive!]
(;B[hi]
(;W[ii]
;B[gi]
;W[ih]
(;B[hk]
;W[hj]
;B[gk]
;W[gj]
;B[ei]
;W[dh]
;B[fk]
(;W[dn]
;B[gm]
;W[fl]
;B[dr]
(;W[fo]
;B[eq]
(;W[er]C[an important cut]
;B[fr]
;W[ak]
;B[ep]
;W[en]
(;B[eo]
;W[fn]
;B[go]
;W[fq])
(;B[pi]
;W[pj]
;B[qi]C[confusing, but there seem to be many options for W to win]
(;W[gp]C[looks frightening, but it played the move it thought was safest.]
;B[qh]C[Chang: this move is worth around 70-80 points!]
;W[gr]
;B[mb]C[chang: oh, but B has to spend another move. Then it is ok. Otherwise, W couldn't play like this.]
;W[ir]C[W has captured the entire lower and left side of the board and still has life in the upper right, so B certainly doesn't have enough.]
;B[mo]
;W[es]
;B[kp]
;W[lp]
;B[jq]
;W[io]
;B[gq]
;W[hp]
;B[hq]
;W[iq]
;B[hr]
;W[mp]
;B[fs]
;W[nn]
;B[jp]
;W[jo]
;B[ki]
;W[kh]C[W+R

B has to spend a move to capture P11. But even after another move, the territory balance is totally wrong.]
;B[rj]
;W[jr]C[Chang: before, we may not have appreciated alphago's reading ability, or skill at dealing with exchanges worth over 100 points.

We still hadn't seen it, but through this game, we see that in large scale fighting, it is still very strong.

Also, after the K12 move, if we didn't have Fan Hui to explain, it would seem very strange for B to come out through that narrow space, and seem that W would be happy enough just to connect underneath.

Or that B couldn't just defend simply at J11, or then it would have no opportunity to win.

This gives us a boost to our thinking.

All in all, this was a brilliant game.])
(;W[qh]
;B[ri]
;W[rh]
;B[rj]
;W[rg]
;B[eb]C[Fan: isn't this half sente though?

threatening C13

Liu: yeah, as W has is short on liberties having to play A7

Chang: oh. No, but it is all connected to F12!

Fan: oh!! oops. it has no effect.

Chang: I've made this sort of mistake professionally before against Wang Dong Liang.

At the time, he made an exchange to capture 3 of my stones, and I couldn't understand why he just wanted to capture just stones. I happily made the exchange, but in waiting for my opponent to resign and give up. But I found my opponent was also playing very calmly. I suddenly noticed that those stones were connected to a large seki. And it should have been me who should be about to resign.

like this if B is dead at O17, even if B lives with E18, it is surely not enough.])))
(;W[ak]
;B[ep]
(;W[eo]
;B[fn]
;W[en]
;B[gp])
(;W[en]
;B[eo]
;W[fn]
;B[go]
;W[fp]
;B[fq]C[W is dead])))
(;W[er]
;B[en]
;W[fn]
;B[fo]
;W[gn]
;B[go]
;W[hn]
;B[in]
;W[ho]
;B[hp]
;W[eo]
;B[io]
;W[en]
;B[eq]))
(;W[fo]C[Chang. like this W loses by one liberty]
;B[ap]))
(;B[gk]C[B can live like this, but it isn't good enough

Liu: I understand. Firstly A8 is worth quite a bit - comparing to if B got A8, the seki would turn into ko.

and furthermore, it has something to do with the life and death of the J16 B group. If it wants to make life, K15 is a vital point, which threatens the K13 throw in. So forcing B to clamp at H11 helps solve W's issues.]
;W[hk]
;B[fk]C[now after K15, the B group is dead

Chang: it only has an eye in gote at the top because E18 isn't completely sente

Liu: heh heh, it looks close to sente.

Chang: because it has to do with the A8 hane that gives W more liberties.]
(;W[bb]C[this is now sente]
;B[]
;W[dh]
;B[cg]
;W[ae]C[B is already dead by double ko])
(;W[io]C[Fan: it thought that W has two ways, both certain wins]
;B[ho]
;W[jo]
;B[hp]
;W[fo]
(;B[gm]
;W[hn]
;B[gn]
;W[go]
;B[in]
;W[ir]C[B is already dead])
(;B[hn]C[Liu: actually just given this position, it would be very hard for me to work out what is happening]))
(;W[iq]
;B[hq]
;W[ir]C[Fan: B also can't fight here

it has something to do with the half dead B group at the top too.

A capture race between the B and W groups]
;B[]
(;W[je]C[Chang:]
;B[jd]
;W[jf]
(;B[jc]
;W[ke]C[W still has this escape])
(;B[ld]
;W[lc]C[B can't connect as B dies too clearly]))
(;W[lp]C[Liu: and this is also absolute sente

Chang: this makes it pretty clear then that B is in trouble

the centre W group has a lot of liberties anyway.]))))
(;W[jj]C[in that case, why doesn't W play here?

if it is sente, W is threatening to kill with G10]
;B[ii]C[Liu: B might just take the two stones

Fan, Chang: oh! yeah!]
;W[ji]
;B[ih]
;W[mj]
;B[mi]
;W[li]
;B[mo]C[Chang: that explains everything]))
(;B[gj]C[Chang: but what if B plays kosumi to live then?

Liu: possible, looks like it, but ??? one problem is that ]
;W[jj]C[this is sente]
;B[mo]
;W[gk]C[Fan: so B has to sacrifice and play E11 in order to live!

Chang: even after E11 it is still dead!

Fan it's already dead!]))
(;W[gj]C[Liu: I thought normally W would defend]))
(;W[mo]
;B[nn]
;W[on]
;B[om]
;W[ol]
;B[pm]
;W[pk]
;B[no]))
(;W[]
;B[pi]
;W[pj]
;B[qi]
;W[qj]
(;B[qh]C[but B can just connect]
;W[pl]
;B[mb]C[W is very dead])
(;B[rj]
;W[qh]
;B[ri]
;W[rg]C[B is not alive])))
(;B[hi]C[W is not completely connected here]))
(;W[pi]C[if just here]
;B[oj]C[the W centre group doesn't look good. and if W has to give up the Q18 corner in order to live, W will need to make profit elsewhere]))
(;B[nf]
;W[je]))
(;B[mf]
;W[oc]C[asking B to atari and connect at O16 to stop W cutting O16 in sente, but then that gives W O13 in sente

Chang: so all of it's moves are to trying to increase the strength of the centre stones and turn them into thickness. And not let them turn into a target for attack. The difference may just be one line apart!]))
(;W[nb]
;B[ob]
;W[oa]
;B[oc]
;W[qa]C[...

Chang: the reason we would like W here is because it seems that these W exchanges help work with the moyo, and it is now urgent for B to invade.

...

for us, if you really go ahead and cut, we realise it is hard to plan against it.

but the difficulty is seeing it from this position

most players would think to reduce, and then the 3 stones can already be used as thickness

and we would think W is ahead, as the L14 stones seem so awkward, W is not behind in territory and still seems to have potential.]
(;B[lp]
;W[kp]
;B[mo]
;W[ln]
;B[mn]
;W[mm]
;B[lm]C[Fan: it thinks that even with those 3 stones, they still don't necessarily help.

...

Chang: but with these 3 stones, W has cut off its own escape route.

And moreover, W would have an extra move on the board, whereever it is.

It looks like the 3 moves have profited, but if there isn't a good enough relaton to the other stones. if B has just enough space to do something here. If W can't capture B, the 3 stones may become a burden.

And the O18 move merely becomes an endgame.

It becomes a question of who is thick or thin in the centre, and the difference may be a very large number of points.

Fan: like this, it actually thinks that B is ahead.

...

Chang: but for alphago, it says that even with the 3 extra stones, you aren't thick!

In fact, you've merely cut off your escape route.

....

Chang: this is very difficult.

For talented players, looking back, such as Go Seigen, Sakata Eio, or Cho Chikun or Cho Hunhyun, Yoo Changhyuk. They all were very sharp at calculation and the balance between thick and thin.

]
(;AE[oa][qa][nb][ob][oc][ne][kf][lg][jh][lh][mh]AB[qb][qc]TW[bj]TB[bf][ag][cg][bn]C[Chang: without those 3 exchanges, W could play moves like]
(;W[kg]C[still aiming at pulling out the G12 stone])
(;W[]
;B[lg]C[and even if B plays a move around here, W doesn't necessarily need to connect up underneath.]))
(;AE[jh][lh][mh]AW[ji][li][mi]C[In fact, if the 3 stones were one step closer, perhaps W could just capture B, but one step further, if W is unable to capture, then the thick and thinness is reversed.

And in fact B can use the fact that B is solidly connected up to counter-attack

Fan: Chang's analysis is very clear.

Chang: in fact, the balance between thick and thin often just happens in a moment.

the 3 stones may now just be heavy

Liu: 3 seconds before, W may have felt thick, but 3 seconds later, it can seem in trouble.

]))
(;B[ik]C[say around here, but]
;W[kk]C[so W can hum a happy tune "I am leading"])
(;B[nk]
;W[lk]C[W connects up, and B still has to invade the other side. 

And after counting, W doesn't need to make much of the moyo, but B's territory has already been reduced.

The L14 moves etc are all dame, and afterwards, W can still play H12, and the C6 group is not completely alive. Even if it lives, if W can get A4 in sente, it is still a good endgame profit.

And at leas tthe O18 move is worth a few points.])))
(;B[]
;W[nb]C[now if W connects, though W can still connect, B can wedge to gain points])
(;B[ii]C[Chang: top pros would probably play here

and only play the other move if this move means B is guaranteed to lose.

But as Fan Hui was saying, this position is even.

Professionals, well no-one would just bow their heads and submit, and die quietly. So if this move would mean you lose, they would certainly fight back even if there isn't much chance it would work.

Though B got a lot of points on the lower right, perhaps the right side isn't so big anymore. We counted the 3rd line territory, but now, you can expect the 3rd line territory at most, as W has more strength in the centre.

So B still has a similar amount of points

Liu: so B still has 40 points

Chang: white?

Liu: the top three groups are still 20 points

30 with the lower left corner

Chang: so does B now think that W is ahead?

Fan: I was also very interested in this question. The follow up moves are very interesting. Alphago thinks that if B plays this knight's move, the game isn't very good for B. That is, this move is a bad move.

And its continuation left me shocked.

]
;W[ji]C[Chang: just to push

...

Fan: for me, the biggest impact was that it looks like W is trying to surround the lower side, and then suddenly decides to push B into breaking W's moyo! And thinks that W is doing well like that!

This was very shocking to me

Chang: yes this is very strange. The critical reason seems to be that W thinks it can't really surround territory on the bottom.

Fan: the territory isn't as much as it looks

Chang: no, its just difficult to surround 

...

so like this W can just push a few times and get 20 points in the centre, and there truly is still a problem at J14



]
(;B[ij]
;W[jj]
;B[ik]C[Chang: normally B would extend]
;W[jk]C[Fan: still push

Chang: oh...
]
;B[im]C[Fan: B would jump]
;W[jl]C[Chang: it just thinks to completely get thick

Fan: it just gives the lower side direction to B
]
;B[hn]C[Liu: B needs to connect

Fan: and W plays somewhere on the right]
;W[oj]C[Liu: around here?

Fan: yes
lets count points

Liu: W still has 10 points in the lower left, and however you look at it, a few more on the lower side

Chang: yes, definitely more than 10 points

Liu: B got 5 more in the centre.]
;B[qj]C[Chang: let's say B surrounds, then B has 50 points on the whole board

W should have 10 points in the centre, as if we are counting the right as B territory, W has some sente moves such as Q9 or Q11.

Liu: Oh, but W's centre might be even bigger than it looks as]
;W[ne]C[Liu: this is sente]
;B[oe]
(;W[if]C[and so is this

wait, if W plays this knight's move, it isn't easy for B

Fan: that's painful!

Liu: it isn't easy to connect

Chang: aah! So B is simply in trouble here. There is fundamental issue with the connection

Fan: can B connect from behind?

...

Chang: even just assuming W doesn't disconnect]
;B[he]
;W[ng]C[Liu: W may even have 20 points in the centre now.

so B has 50 points W has 50 points

Fan: it is hard to pay komi

Chang: So that is why B can't play like this

so in other words, our previous judgement that this game was even was probably wrong, and W was already ahead

Fan: no, it still thinks W is ahead, but it just thinks J11 is bad direction.

Chang: oh, so its because J11 is a bad move! and not  ...

but I have a question, as if F7 was sente, and B had to connect, then extending with F7 was a pretty big move, ...

perhaps my earlier judgement of the balance between W's influence and B's influence wasn't sufficiently accurate

if at the moment before the N3 invasion, we could count F7 as being sente, then I would definitely prefer W.

The reason I was still judging the game as even before was because I hadn't counted the F7 for D7 exchange.

if W covered at N4, B could sacrifice N3, but M5 was a good move, and just after 3 exchanges, my judgement of the position changed

At least if it were me, I certainly would start to prefer W.

])
(;W[he]C[Chang: in fact, what about this most crude move?

Liu: it looks like B can't connect])
(;W[de]C[Chang: in fact, might this connection be sente?

Liu: oh, if so, then B is definitely in trouble and J14 will certainly disconnect

Chang: with this move, W has the option of starting a ko



]))
(;AE[jh][ii][ji]
;B[]C[...

...

Liu: my feeling is that in this position, there are many possible moves, whether to play in the centre, or to reduce the right

but as professionals, we are very clear that the strength and weakness and thick and thinness of both sides is of critical importance.

right now, the W stones at M5 are actually very thin, B can cut at M4 or at N6

and B's centre isn't actually very thick either.

so in the latter half of the game, I feel that a sense for thick and thin can determine whether you win or lose.

Chang: And also, I increasingly feel that when we judge the lower side, it looks very wide, with lots of potential to make territory, but it isn't actually where you should be looking to make points.

One thing is that there is the J3 invasion and the attachment at L2

and another thing is that even when you have defended against those, the P5 stones may still be hanging (see J3 variation)

...

Liu: so in the latter half of the game, the game is decided by accurate judgement of thick and thinness.

but this is very hard for us to manage

Chang: at this point, probably if I were to play, I may choose K12, but I may also choose J8. But then

(see variation)]
(;W[il]C[Chang: if it surrounds here]
;B[iq]C[it is scared B will invade

Fan: there is still a hane at E6

...

Chang: But when B invades, it becomes a very unclear fight. Perhaps the game was fine and balanced, and then it may suddenly become reversed if you can't manage it well.

Fan: if B lives with a few points, you won't be able to see a future for W.

Chang: the balance of territory will completely go wrong.]
;W[jh]C[and then if you play this now, B may just play simply to connect up

...

Fan: this move makes what looked like B thickness, it no longer looks so thick. It highlights the thinness.]
;B[ih]C[and W won't be left with much])
(;W[iq]C[Chang: but if you directly surround, for example by jumping here, ]
(;B[il]C[and let B get this move!

then, it is still a question of the centre])
(;B[lp]C[...

even if W has defended the territory, this is very painful ]
;W[kp]C[you have to block]
;B[mo]
;W[ln]C[the P5 stones are hanging]))
(;W[ji]
;B[ii]
;W[jh]C[Chang: but in the game, as W gets thick in the centre, W no longer has to block M4 with L4, and can respond at N5 instead to save the P5 stones

W can let B get out at L4 and M4, and only needs to ask for 3rd line territory on the lower side

W just needs to connect, and doesn't need to  ...

The lower side isn't as big as it looks! It looks wide, like a moyo for development, but ...

Fan: it seems to be that if you turn it into territory, it becomes small, but if you don't, then you still have territory there. It is awkward for whoever plays there first!])
(;W[]
;B[lp]C[Chang: and if you don't spend a move to surround, then B can't play here to capture the 4 stones! ]
;W[kp]
;B[mo]
;W[ln]C[as now W is solid, W saves a move having to defend against J3!

Fan: yes, that's right

Chang: and the other reason is that there really is an issue at J14]))))
(;B[]
;W[nb]C[without this, B won't be able to get that exchange]
;B[qb]
(;W[nd])
(;W[oc]))
(;B[nb]C[Chang: in this position

Liu: B loses a point with R18

]
;W[sd]
;B[se]
;W[qb]
;B[oa]
;W[pa]C[Chang: as W can't keep the points up to here, as W will eventually have to defend against the S18 piercing move to get a seki when all te liberties are filled.]))
(;W[dh]
;B[cg]
;W[de]
;B[al]
;W[ai]
;B[ak]
;W[ag]C[one step ko, W can't play like this]))
(;B[dm]C[Fan: and B connects!

This reminds me of the peep and cut in Wuzhen against Ke Jie.

Chang: yes that move, there was no direct follow up, but a lot of lasting aji.

Perhaps it is a bit similar

A gote move, with no immediate threat, and B can't hane in at E6, but it reinforces your own shape and leaves some aji.

...

Liu: so this move seems strange

Fan: it seems interesting

Liu: because, though the cut can't kill B, there is a lot of aji in the centre.

Chang: and because W can retain the right to choose between D7 or A8, only cutting when necessary, as B's A8 isn't completely without value.]
;W[ai]C[...

Chang: but if you don't push, W can directly atari]
;B[dj]
;W[de]C[and W saves a liberty]
;B[cj]
;W[bb]
;B[bj]
;W[dh]
;B[cg]
;W[ae]C[this is now a direct ko, so given that B is going to connect, B must first exchange the push. Otherwise now the 4 white stones have become light

Fan: the F7 for D7 exchange have become a clear profit.])
(;B[al]C[Fan: locally doesn't this move live. Then W can't kill B with the cut, 

...

Liu: let's see after this move, what the semeai is like.

...

Liu: hence this move is not sente. Whether B pushes or wedges, W always has something

Chang: with the E11 sente, B has at most something in sente on the outside (G10), but at the moment cannot kill W.

Fan: like this the D7 cut remains]
(;W[il]C[Fan: W would play here

...

Fan: alphago thinks this exchange is good for W

Chang: of course, if there is nothing B can do on the left.

...

Liu: so is there anything else B can do?]
(;B[dj]
;W[cj]
;B[ag]
;W[de]
;B[ak]
;W[bb]
;B[ai]
;W[dh]
;B[cg]
;W[ae]C[Chang: this is a direct ko, but B can't fight this without worry as B is a bit heavier than W with more stones.

W already got 2 moves on the outside and will get another 2.

Liu: because in this ko, B already lost a move, playing A8.])
(;B[cj]C[Chang: how about the wedge? yes.]
;W[dj]
;B[ak]
;W[de]
(;B[ag]C[Fan: but W has a move

...

Liu: ... so neither side can atari.

Chang: this atari (D12) is like a shared liberty. You can't play it without care. At least W can choose which to play.]
(;W[dh]C[Chang: if we still play here]
;B[cg]
;W[bb]
;B[ai]C[now W is unconditionally dead, and then it would be terrible for W])
(;W[ei]C[Liu: oh!

Chang: so D12 actually short W's own liberties]
(;B[gj]
;W[bb]
;B[ai]
;W[bj]
;B[cg]
;W[ae])
(;B[ai]C[Chang: and you can't play here. W has 3 liberties! You can't fill them from C13 or A10.]
;W[fj]C[Chang: very subtle!])))
(;B[ei]C[Chang: this semeai is really very subtle!

if B directly fills this liberty]
;W[dh]
;B[cg]
;W[bb]
;B[ag]
;W[ae]C[it is seki

it is as if you filled the E11 liberty when you should have played A11.

This position is very interesting.])))
(;W[bb]C[Chang: if W had to respond and A8 was absolute sente and B already made this exchange, then B wouldn't connect at D7. The value would be too small as the cut is gote.])))
(;W[or]C[Liu: it looks like W can't play here anymore]
;B[lp]C[liu: just the most crude move works

chang: it feels like trying to use paper to contain fire]
;W[kp]
;B[mo]C[W collapses]))
(;W[mp]C[Chang: our normal instinct is to cover]
;B[lp]
;W[lq]
;B[mr]C[Fan: it thinks W is in trouble.

Chang: the problem is that W can't ladder the stone, otherwise it would be fine.]
(;W[mo]C[but if you extend, that's much worse]
;B[or])
(;W[or]C[Liu: so W probably has to descend]
;B[mo]C[Chang: so B will sacrifice. This atari is very comfortable]
;W[np]
;B[kp]
;W[jq]
;B[jp]
;W[iq]C[Chang: the centre has taken form

so the territory on the right is very interesting

If in the surroundings W is solid, W doesn't even need to invade and just reducing from the 5th line makes B uncomfortable. Taking the territory means it is 3rd line at most and W still has a few moves in sente.]
;B[on]C[Liu: but if B seals in here, don't talk of 5th line any more, ]
;W[lg]C[probably this is the deepest that W can go

Chang: otherwise if B gets this point, then !!!

Fan: and B didn't seem to lose many points giving up N2, with the liberty filling.

Chang: yes, now we can see the cost of the Q4 for R3 exchange. In this position, it really seems to lose the value of one move.

Fan: that's too big.

...

Chang: so here, it is really making an example of how much W loses with Q4. It isn't just losing a little, but maybe really a whole move's worth.

Fan: so it is still a problem of efficiency]
;AE[pp][qq]C[Chang: because the Q2 block is gote here, but in the game, it becomes sente

]
;B[]
;W[qr]C[but W can play here if you don't])))
(;B[]
;W[oj]C[Chang: I'll play on the 5th line too, learning from alphago!]
;B[qj]
;W[pi]
;B[qi]
;W[ne]
;B[oe]
;W[nm]C[Chang: just giving B all the side territory, now who do you feel is thicker?

It's almost been completely sealed in by W.]))
(;B[dm]C[Liu: B can't play here?]
;W[ah]
;B[dj]
;W[cj]
;B[aj]
;W[dh]
;B[cg]
;W[bc]
;B[ak]
;W[ag]
;B[ai]
;W[ae]C[so W wins]
;AE[dm]AB[cm]C[Liu: but in the game, W can also play like this

Chang: so it is a direction ko, and B has threats with C2, so W can't play like this.]
;B[cr]
;W[br]
;B[ei]))
(;B[dj]
;W[af]C[Fan: the different in liberties isn't large]))
(;W[dm]C[Liu: so W chose to cut over there, rather than over here, what if it cuts here?]
;B[cm]
;W[bl]
;B[ek]C[Liu: this looks like B has a sacrifice variation

Chang: there is the possibility of a sacrifice variation. Directly playing the semeiai, W seems to win

Liu: the semeiai is definitely good for W.

Chang: W has a little more liberties.]
;W[]C[...

Chang: so actually B's play here is aiming at the weakness in W's shape above.

B has a cutting point (E12), and so does W. Both sides have cutting points so the focus of the game ... the D8 attach looks like the focus is the 4 stones (C6), but actually the focus is not entirely over those stones, but the whole fight.

Fan: both sides owe debts

Liu: including the top side fight

Fan: this fight becomes global]
(;B[gg]C[Fan: and B has this powerful cut]
;W[ff]
;B[hg])
(;B[ff]C[Chang: this cut is even more powerful]
;W[gg]
;B[ge]C[Chang: there's no good move.  If W doesn't play, B takes the two stones in sente, but ]
;W[ed]
;B[hf]C[if W connects, B tiger

this is a very severe cut

])))
(;W[dm]C[Liu: what is W scared of?]
;B[ck]
;W[dk]
;B[bk]C[Chang: oh wow, this is so much better. The important thing is that B connects underneath, and saves the other group as well! This is too much better!

Liu: the efficiency is very high]
;W[el]
;B[bi]C[Chang: B connecting up compared to crawling, you can't describe how much better this is!

Liu: better by 2 moves worth!

Chang: such from looking at this, you can tell

Fan: there's no need to quantify (to count) it

Chang: it's just clearly better]))
(;B[eh]C[Liu: and it isn't even easy to defend the cut

Chang: like this, B would have been better playing E12 empty triangle directly rather than F12!]
;W[bl]C[but B has no time as this is such a big capture

Fan: the B shape is tragic

Chang: so B definitely can't connect])
(;B[bl]C[Chang: but if B just crawls]
;W[ck]
;B[cm]C[Chang: then with B10 sente, when W hanes at B12, B runs out of eyespace]
;W[eh]C[Liu: so W can just cut?

Fan: don't know what to play anymore]
;B[]
;W[bi]C[Chang: and even this move has sente aji, after the attach (A8), B is not alive]))
(;W[cl]C[Liu: the bump does actually seem to have a meaning]
;B[ff]
;W[gg]
;B[ge]C[later, B can cut light this

Chang: in other words, W may want to sacrifice the F16 stones later

if I sacrifice them, the J17 exchange is very good, so it is a necessary move order

Fan: yes, it isn't just a random move or timesuji

Chang: is there a time limit.
Fan: 2 minutes

Chang: so very slow for it.

Fan: So in a whole game, it tends to play a lot of moves

Chang: like 300 moves, lets just call it something more normal, over 200 moves

Fan: say 250 moves

Chang: 500 minutes, over 8 hours

Fan: absolutely not a fast game

Chang: because I saw at the Wuzhen match with Ke Jie, it never used up much time in the 3 hour match, always just using up 1 hour, never reaching 90 mins.

Fan: it depends on how many moves are played in the game

Liu: I have a question. Is there a skill difference between 2 mins and 30 seconds per move?

Fan: 2 mins is clearly much stronger

Chang: did you have a match to back that up?

Fan: er, this isn't how we analyse it. I don't think we had such a match. It was judged another way.

At the least, with more time, the search is deeper and analysis is more precise.

Liu: So all the 50 self-play games and this set are 2 minutes per move and very high quality.

Chang: even for humans, 2 minutes a move is very long

Fan: and it's for every move, including 2 minutes to respond to an atari.

Liu: understood.

Chang: but it is different as it is making many calculations, whereas we might spend all of our time on one move, and just a few seconds for the rest.

Liu: just like the upper right, in the attach variation

Chang: yes, for us, if we attach, we've already decided that we will double hane, and B is already clear, there are just a few possible variations, so if you pick one, you follow it up naturally in a connected sequence

Fan: and 10 moves can take 5-10 seconds.

Chang: but it will spend 2 minutes responding to an atari

Fan: it isn't just thinking about the current move, it is thinking about all the following moves]))
(;W[eh]C[Liu: is B really not scared of the cut?]
(;B[cg]C[Fan: alphago was planning just to simply connect

Liu: not atari or tiger

Chang: it says the centre stone is light

...

Chang: directly connecting makes it harder for W to disconnect]
(;W[gg]
;B[ci]C[Chang: if W extends, B is happy to attach and let W ladder])
(;W[ci]C[Chang: it's embarrassing to still play here. If you still iron pillar, B's connection is much better than tiger as it doesn't short liberties]
;B[fi]C[Liu: so B may fight strongly and B is better shape and better liberties

Fan: and the corner still has trouble]))
(;B[ch]
;W[ci]C[Liu: if B tiger, W certainly blocks])))
(;B[eh]C[often you can only come out like this]))
(;AE[gc][gd]C[Chang: if W peeps now, ]
;W[gd]
;B[fd]C[B will certainly fight]))
(;B[fd]C[Liu: so I'd like to ask what if I don't want to give you such a comfortable shape?]
;W[gc]C[Chang, Liu: oh

Fan: because it is focused on the C13 cut weakness

Chang: so it is always threatening cut. Though it loses points, it gains the turn and connect sente, and W isn't scared of this fight.

Fan: it is constantly threatening B's life. It is hard for B to move.

Liu: if we view it as]
;AW[bg][cg][eg]AB[bh][ch][dh]C[Fan: shouldn't W preserve E13
Liu: let's say, even just using the turn sente
Chang: even then ...

Liu: with the D13 sente connection sente, if I peep G16, and you dare to fight back, of course I fight here.
]
;B[fe]
;W[fb]C[B will die if B continues down]
;B[ge]
;W[hb]
;AE[eg][dh]C[Liu: so it is like this

Chang: and W is threatening to hane out at H15, but if B protects it is too slow.]
;B[]
;W[cl]C[Liu: and B is still pretty uncomfortable when W presses down

Chang: because the C13 cut didn't actually lose so much here.]))
(;W[fd]
;B[gd]C[Chang: it's much better shape than directly attaching.

Because W does owe a move and sooner or later needs to defend the D15 cut.]))
(;AW[di]
;B[eg]
;W[gd]C[Chang: so W shoulder hits and is still planning to harrass B here.

So when B is weaker and W is stronger, W must connect, but]))
(;W[db]C[Chang: so in this situation we would normally tiger.

From a defensive point of view, this move is better, since if B cuts]
(;B[de]
;W[ed]
;B[ee]
;W[fd]
;AE[db][cc]AW[cd]C[it's similar to this joseki, W isn't scared of B pushing through])
(;B[gd]C[and if later you threaten the cut, then]
;W[de]C[when I connect, D18 is still well placed for eyespace]))
(;W[ec]C[Chang: alternatively we can play this]
;B[bc]
;W[fd])
(;W[fd]C[Liu: I think we've seen alphago play here, when the left is not so big, but most of the time it connects D17.]))
(;W[ce]C[Chang: and it never wedges. The efficiency is truly a bit low.

Fan: the shape isn't good.

Chang: I don't think I've ever seen it wedge.

Fan: it never wedges.
])
(;W[dc]C[Fan: though sometimes it will descend and then cut C13]))
(;B[ce]C[Fan: it has extended too]))
(;W[fc]C[Chang: If W responds?]
;B[dn]C[Fan: W's next move is interesting. It will struggle between two moves, neither of which is easy to guess.]
(;W[ei]C[...

Chang: but its thinking is that even if I play on the 5th line, I'm not scared of you taking the 3rd line territory.

If we go 4th line, it is impossible that B will play on the 2nd line. But before we thought that if we play 5th line, it is possible that you play 3rd line.

But now it thinks that W's not even afraid of B playing 3rd line. So if not, then why not play further out, so W can run out faster.

Fan: When I was learning go, we would think that the top was one direction, the left, the lower side and so on, but for alphago, it seems the centre is also a important direction of play here.

Chang: I think the reason alphago's plays so differently with regards to the centre is that it is so hard to make judgements about the centre. We can consider Takemiya again. It was very hard for others to copy his style. Because the value of the centre is very hard to judge.

Fan: there's no way to quantify it.

Chang: because the sides and corners are quantifiable, like asking how many points is this endgame move. And the whole of human go history doesn't have that many game records, let alone the number an individual can play in their lifetime.

So most often our judgements come from our own thinking rather than from large numbers of games or watching large numbers of games.

So our judgement of the centre is less based on calculation and more based on feeling.

And so people don't dare to play in the centre, because you can't tell how much it is worth. We just don't know.

It's easy to calculate the effect on the sides.]
;B[ci]C[Chang: but one stone like E11, how much is it worth for the centre?

We often use logic, such as counting points and if it comes up the same, then one stone like E11 will certainly have some worth.

But if the opponent gets more on the side, we tend to be unwilling to sacrifice those points, as it is very hard to use this centre stone to claim back the points we lost on the side.

Fan: this makes me think of another move, the move 37 against Lee Sedol

Chang: The 5th line shoulder hit.

Fan: for alphago, it struggles to decide whether C11 is a good move

Chang: Oh, I was thinking the 5th line shoulder hit in the pair go with Gu Li.

Liu: Lots of 5th line feeling.

Chang: It has a sense of the 5th line. I think it is because it has so much data, it isn't so afraid of giving away the side. Its sense of the centre is very different to ours.

We just play based on normal experience, it's very hard to get enough data.

But it depends on huge amounts on data, and self-play games, to reach this sort of.

Fan: our experience is also based on data, it's just that it is hard to quantify, but we can qualitative (?)

Chang: it is just that in the face of computers, our quantity

(laughter)

it's too few.]
;AE[fc][dd][cf][ci][ei]AW[dc]AB[ce]C[Fan: when I was playing it out with Liu earlier, he told me he had played a related move

Chang: oh yes, ]
;W[eh]C[Chang: was it here?

Fan: yes, yes

...

Liu: We both young around 15 or 16. Our go was more unrestrained then. And because it was a new stars competition, not an important international tournament.

I thought for 10 minutes and thought this would be fun. And he took this as asking for a battle of strength

Chang: "how dare you play there!"

Liu: he thought for 20 minutes and attached.

...

Fan: if there are more of these moves in the future, I think it would be a lot of fun for amateurs.]
(;B[eg]C[Chang: did he attach?

Fan: yes, Choi Cheol-han played there

It's confusing to replay.

Liu: this was over 10 years ago]
(;W[fg]
;B[dh]C[Liu: in a new stars competition]
;W[di]
;B[dg]
;W[fh]
;B[ff]
;W[gf]
;B[fe]
;W[gc]C[Fan: it feels like W is very good here, playing a good tune, B's efficiency doesn't seem very good.

])
(;W[dh]C[...

Fan: if W descends, it is like B played the elephant eye shape.]))
(;AE[eh]AW[jd][dh]C[Chang: I played this sort of move myself against Wang Yao]
;B[ge]
(;W[fe]
;B[ed])
(;W[ed]
;B[eg]C[Chang: I originally thought that if he kosumi I would play here

Fan: oh! That move is very pretty.

Chang: because the Kobayashi fuseki was very popular then. I think it was 2008 in the Chunlan cup.

Fan: Having taught go in the west, I've felt that fun go is an important aspect of go. This sort of go feels very fun.])))
(;W[eh]C[Chang: both 5- line

Liu: quite interesting.])
(;W[ch]C[Liu: we would normally think to pincer close])
(;W[di]C[Chang: or 4th line

...

because B has a ponnuki, W isn't trying to attack B.]
;B[bi]C[Chang: because I'm not scared of B playing underneath])))
(;AE[pn][oo][po][op][pp][kq][pq][qq]C[Chang: In this position, R4 is clearly worse placed, ]
;B[pq]
;W[op]
;B[po]
;W[oo]C[letting W get this is awful for B too]
;B[pn]C[B is overconcentrated]
;W[kq]
;B[]
(;W[pp]C[of course, this is bad, losing points and liberties]
;B[qq]C[for Takemiya, the big direction was more important and you didn't need to be so concerned with small local details.

But the Japanese go culture at that time was particularly concerned with details like liberties, aji, preserving variations, these sort of tools. Delving into this sort of precision.

I think perhaps it has something to do with the culture, with some relation.

They would be particularly upset, saying this loses a liberty, or loses aji, and so on.

But for Takemiya, yes this squeeze is very bad for W, but in the global picture and direction of play, I have profited.

He did say and conclude that sort of thing before.

Fan: The two sides are complementary. W gained in direction and B gained locally, so it is about even.

Liu: so this result, even alphago thinks it is even! Both sides can accept it.



])
(;W[or]C[it's concerns this too.])))
(;AE[ql]AW[cn]AB[jp][fq]C[Chang: the Kobayashi fuseki was very popular then. Of course without the top right.

Hearing Takemiya played it, well, you think he can play anything and it is not too surprising.

It's just like how we say "alphago played this". Firstly, you don't dare to tell this move off.

His young opponent, if it wasn't Takemiya and just an amateur, he would probably tell him he doesn't really know how to play go.

(laughter)

Chang: they can only say Takemiya sensei played it. Whatever he plays, it is not surprising.

It's like I was saying before. For many of alphago's moves, it isn't that humans haven't played them before. Including the 3-3 invasion which has been played so many times. It is just that the situation is different, the timing, the surroundings. Actually this attach was played quite some time ago.

Fan: When you speak of Takemiya. Because European players particularly love his play. Feeling that is it very natural and bold, not restricted in a box.

For many of these alphago moves, like this attach, whether they are good or not, they bring an open minded way of thinking, breaking the boundaries of our boxes. This is good news for go players, with more variations available.

Chang: for professionals it is the same. Yes, but it is very difficult. 

Without a set of joseki as a foundation, that's impossible. But humans are creatures of habit. As soon as you have this foundation, it is difficult to forget it. You will still be restricted by it, even if you tell yourself not to be, perhaps that is an innate skill.

This is the quality of alphago. It isn't affected by 

Actually, you speak of Takemiya, he quite famously can't do post game reviews, and forgets even important matches after a few years. Most famously in the Honinbo or Meijin, against Otake, in the large avalanche, he thought for 5 hours on one move.

Though it was a 2 day competition, 5 hours is still very long, and no-one knew what he was thinking about.

After it ended, they asked him. He said "because I forgot the joseki".

Fan: Oh yes, I've heard that.

Chang: and in life, this sort of this happened so often. Takemiya is renowned for his forgetfulness. At least that was Fujisawa Shuko's appraisal. You can't assign any job to him as he will certainly forget.

So maybe Takemiya isn't so restricted by these things as he can't remember them anyway!

Each move he plays is just what he thinks is good them. You don't discuss plans or research beforehand, because he won't remember them anyway.

Fan: (not sure, just my vague guess) if you are unbiased in heart and method, that is impressive.])
(;B[qq]C[Liu: like this, maybe it's a bit too submissive]
;W[np]C[Chang: it probably won't even be as good as R4, the shape won't be as good.])
(;B[op]C[Chang: W surely takes the corner]
;W[qq]
(;B[qp]C[Fan: firstly B surely can't cut right?]
;W[po]
;B[rq]C[liu: atari seems the only move]
;W[oq]
;B[qr]
;W[pr]
;B[qq]
;W[np]C[Fan: B's efficiency doesn't seem right

Chang: globally W seems better

Liu: whether globally or locally, it should be good for W.])
(;B[oq]C[Chang: hmm, or is atari better?]
;W[qp]
;B[po])
(;B[po]C[Liu: let's say]
;W[qp]
(;B[oq])
(;B[or]C[Liu: can B tiger? is it better than connect?

Fan: yes, but W plays quite simply]
;W[pr]C[L]
;B[oq]
;W[rn]C[Chang: it thinks living it the corner is comfortable, more so than approaching it.

Liu: life is pretty comfortable]))
(;B[qr]C[Liu: is there no way to attack W more?

Fan: double hane is the strongest move.]
;W[qp]
;B[or]
;W[oo]
;B[np]
;W[qm]C[Chang: yes, my feeling was that it would attach]
(;B[rm]
;W[pm]
;B[rn]
;W[rr]
;B[rs]
;W[no]
;B[mo]
;W[nm]C[chang: after just a few moves, B's seemingly big moyo has been reduced perhaps just to 3rd line territory and less than 20 points.

and W will certainly get sente

this is definitely good for W

Fan: it thinks that this is slightly better for W, but not by much. That is why B didn't play this.])
(;B[pl]
;W[pm]C[fan: and both sides tenuki

chang: it just wants to settle, that's all

liu: so B is thick and

chang: so the N16 exchange is good])))
(;B[oq]
;W[qp]C[Fan: it would play simply]
;B[qq]C[Chang: have to block]
;W[rq]C[normally have to block]
;B[rr]
;W[ro]
;B[sq]
;W[om]C[liu: this is very interesting.

amateurs can try this sort of shape in their own games in similar situations]))
(;B[oe]C[Chang: or maybe it thinks that later, B may defend like this to remove the O15 peep

...

Chang: but this is worse in the centre, so it is actually a probe, will B turn or jump? If jump, then signature move.

Fan: maybe if turn, it won't be the signature move.

Chang: there might be something else.]
;W[mc]C[Liu: and it is very different when W blocks]
;AE[oe]AB[of]))
(;W[pf]C[Chang: though, maybe now you wouldn't connect as it is heavy and B has more stones helping, but in the future, if the surroundings change.

Liu: that is entirely a possibility]))
(;B[pc]C[if you take sente now, ]
;W[re]
;B[cc]C[Chang: at least W is settled and safe, without any of the aji of attaching R13, without B having the right to choose either the corner or the outside.]))
(;AE[qd][ql]AW[qo]AB[np]C[Chang: in the Ke Jie game it did too, with such a wide space, of course with the colours reversed]
;B[]
(;W[qd]C[it also attached])
(;W[pj]C[when we would normally play on the side

so this is very interesting

Liu: very interesting.])))
(;AB[qi]
(;W[qd]C[then this is normal]
;B[qc]
;W[rc]
(;B[pc]
;W[re]C[S15 is clearly much better for eyespace than S16. The difference is quite blatant.])
(;B[qe]
;W[rd]
;B[pe]C[and W can choose to take the corner or make shape on the outside.

W settles this group faster with the attachment.]
(;W[pc])
(;W[re]
;B[qb]
(;W[rg])
(;W[pf]))))
(;W[rd]
;B[qc]C[W is uncomfortable as W still doesn't have enough eyespace]
;W[rc]
;B[]
;W[qd]
;B[pc]C[the most you can get is this shape]))
(;W[rd]C[this is normal when W has space

...

Liu: there is a question though, that if I don't ask, I'm sure many viewers will ask. It is that if W really does play knight's move, what would B do?

Fan: I did think about this too, wondering if it was something very complicated like R13

Liu: Because it feels that whether B takes the corner or pincers on the side, B's isn't satisfied.

Chang: Yes, because we mentioned B playing the 3-3 before gives W a comfortable 2-space, but 

...

Fan: so alphago would neither pincer nor take the corner, ]
(;B[qc]C[Chang: now it is unlikely that B plays 3-3]
;W[qi]C[as W has space for a 2-space, a very comfortable space and base.

This is very different from what we learnt as kids.])
(;B[qh]C[if we play out the most standard joseki]
;W[qc]
;B[qe]
;W[re]
;B[pf]
;W[pg]
;B[qg]
;W[rf]
;B[og]C[then it is clear that B's R8 is too close.

Because it is a bit "中途半端" (i.e. non literal "chasing two rabbits and catching none).

Here, if W has the ladder, running out is still very severe]
(;AE[ql]AB[pj]C[here it would obviously be good, defending the ladder])
(;W[jp]
;B[ph]C[but if B still has to defend, R8 is too close to thickness. Too overconcentrated. If at Q6 or R6, that would be ok, but he, that, that ...]))
(;B[cc]C[Fan: it would play 3-3

(laughter)

Chang: it's always the 3-3 invasion!

Fan: and we can't ask more, it's too complicated

Liu: if it's 3-3, we all understand now.

Chang: After seeing the 50 self-play, we're all familiar with 3-3 now

Fan: territory obsessed

Liu: and being scared of 3-3 explains why it doesn't like the S16 keima.

Chang: It is also very curious. In the self-play, it knows that it will invade 3-3, but it still plays 4-4!

It must think both are ok. If it thought the side that played 4-4 was not good, it wouldn't play 4-4 anymore.

Fan: it thinks it is a normal joseki

Chang: but it still plays 3-3 when it can. 

(laughter)

Fan: it is an urgent joseki, it's time to play it.])))
(;B[qe]C[chang: just recently it kicked against ke jie])
(;B[fc]C[chang: oh, though it approached first before R8]
;W[cf]
;B[qe]C[and then]
;W[pf]
;B[nd]
;W[pi]
;B[qj]))
(;AE[ql][pq]AB[qp][oq]C[Chang: and it always encloses two space low or high.

This opening was very popular 20 years ago, but Master Wu was saying how this is unacceptable for B. And it was to do with the large komi.

When Master Wu started playing, there was no komi. Later it went up to 4.5, 5.5 and now 7.5. And he was saying how B cannot play the small knights against this komi, and it must be the large knights or the one space jump]
;W[np]C[and he would immediately play the shoulder hit

and without P3, he would also approach he, because he wasn't afraid of P3.

But us go players loved territory too much and would be very happy to take the enclosure given his sort of approach.

But he would say that even if W tenukis here B has already lost out.

Back then, we were like what??, and couldn't understand. But with respect for Master Wu, we didn't dare to argue.

And because this isn't something that we can make a clear conclusion on from just playing out variations.

Because go has a lot of abstract things, and this move will have an influence on the centre, and he concluded that in the era of komi, black couldn't play here, and would be behind.

But in those days we were territory obsessed. But of course a few players tried it out, including me, but most players would still feel it was easier to handle the side who took territory.

Master Wu didn't have any competitive games then and he would like us to try his ideas out in competitive games.

In the Master (alphago) series, there are a lot of Master Wu's plans and ideas from the latter part of his life. Perhaps this is how 21st century go should be played.

Fan: for alphago, it is the same. For B to make an enclosure, it would prefer the other moves and pretty much wouldn't make the small knight's, but W may.

Chang: This is the same as Wu's advice. He said that in the era of no komi go, the small knight's enclosure was a good move, a proper shape. Especially in the famous Shusaku opening.

]
;AE[pd][np][qp][oq]AB[qd][pq]
;B[oc]C[chang: making this move!

liu: then this game would pretty much be set!

chang: they would ask shusaku how his game went, and all he would have to say was "I was black"

(laughter)

so everyone would know the result.

But Master Wu said that with the change in eras, you can't just copy old moves, with the change in rules with komi.]))
