(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[shift_jis]
GN[2017.10.20_AlphaGo_selfplay_12]
PW[AlphaGo]
PB[AlphaGo]
EV[AlphaGo selfplay]RO[12]
KM[7.5]
RE[W+R]
RU[Chinese]MU[1]
C[AlphaGo vs AlphaGo Game 12
Commentary by Michael Redmond 9P
Editing/transcription by Chris Garlock and Myron Souris

In this game we start with a variation of the mini- Chinese opening, so we're going to have another of these 3-3 invasions. It's a really interesting opening, and it's one of the games that ends in a collapse, so it's an unusual game in that way. ]
;B[pd];W[dd];B[qp];W[dp];B[fq];W[cn];B[lq];W[qc]LB[qj:A][qf:B]
C[This position occurred 3 times in the self-played series of games, and AlphaGo invaded at 8 each time.  This is a position in which a human with White would usually play at A or B.]
;B[qd];W[pc]
C[Black has three choices now.  It chose one in this game, another in the other two self-played games with this board position.]
(;B[oc];W[ob];B[nc];W[nb];B[mc]
(;W[qk]
C[White's invasion leaves room for an extension on either side making it the natural way for White to enter the right side.]
(;B[pk]
C[The joseki in the upper right makes this position unique, but even so, Black's tsuke here resembles aggressive moves played in similar mini-Chinese openings in modern Go.]
(;W[qj]
C[White pulls back, moving towards the wider part of the side.];B[pm];W[mb]
;B[lc];W[rm]LB[ql:A]
C[White's slide prevents Black A and makes eye space for White's group on the right side.]
(;B[fo];W[oq]LB[eq:A]
C[I would want to play at A first to reinforce the lower left corner.];B[po]
;W[qh]LB[oe:C]
C[White induces the marked exchange, which in turn makes White 26 necessary.  White started this exchange to make a natural flow of moves for White to play this one space extension.  White plans to attack later at C.]
TR[po][oq];B[cq]TR[fo]
C[With the marked stone, Black's invasion to the 3-3 point is a strong attack that is often seen in pro games.]
;W[dq];B[cp];W[do];B[dr];W[er];B[cr]
(;W[fr]
C[Crawling with this important point, before connecting on the 3rd line, is correct.]
;B[gq];W[iq]
C[This aggressive move heats up the fight on the lower side.  White's idea is to reduce the lower side, which is a valuable area.]
(;B[bo]LB[eq:A][gr:B]
C[Simply living here leaves Black the option of cutting at A or covering at B, and this gives extra resilience to Black's group and shows AlphaGo's flexibility.  However, it also gives White some extra options.]
(;W[kp]
C[White moves out before trying to connect on the side.]
(;B[jr]LB[gr:A]
C[The lower side started out as Black's moyo, and Black cannot afford to lose the marked stone.  Black's tenacious move here prevents White from connecting at A, and threatens to push through on the 3rd line.]
TR[lq]
(;W[go]TR[fp]
C[This tesuji makes use of the weakness at A in Black's shape to reinforce White on the right.]
(;B[jq];W[jp];B[lp];W[fn]
C[An important point.  My feeling for the position is that this must be good for White.]
(;B[ip]TR[jr]
C[Black has been aiming at this cut, which forces a trade, from the marked move.]
;W[hp];B[io];W[hq];B[jn]TR[jp:kp]
C[This kosumi is an efficient way for Black to capture the 2 marked stones.]
(;W[qr]
C[White grabs territory in the corner.  It will not be easy for Black to kill this group.]
(;B[rr]
C[Black offers a trade, and is correct in this case.];W[rq];B[qq];W[sr];B[rs]
;W[qs];B[gr]
C[Black's descent here is worth more than 10 points in territory, and gives Black some potential to attack the outside group, so it is a big move.]
;W[eq];B[fp];W[gn];B[ir];W[im]LB[dj:A][dm:B]
C[Although I would choose to play at A instead, I can see the value in controlling the center with this move.  White needs to add a stone to this group to forestall Black's attack at B.]
;B[dk]
(;W[el]
C[White connects to avoid Black's cut.]
(;B[pr]
C[Black's move was the biggest for territory, but it was more important to play on the left side.]
;W[ss];B[or];W[cg]
C[White's move is a big point that controls the left side.  After this, Black is hampered by the weak group on the left, and the game starts to look like a win for White.]
;B[ek];W[bn]LB[en:A][an:B][am:C]
C[White's thick move here protects against Black A, and sets up a forcing move at B or C.]
;B[rp]
C[Black's move is big, about 20 points.];W[oe];B[pg];W[qg];B[rc];W[rb];B[re]
C[Black uses this forcing move to take sente.  ];W[sc]LB[od:A]
C[I have noticed that AlphaGo tries to avoid connecting at A.  I guess that AlphaGo thinks it to be inefficient.]
;B[gj];W[ij];B[ci]
C[Black tries to make a base on the left.];W[od]
C[White cuts to start an attack.];B[pf];W[nf];B[oh];W[kd]
C[White's move here controls the upper side, while lending a hand to the relatively weak stones on the right.  By controlling the center, White prepares to attack Black's group on the left later.]
;B[kc];W[id];B[lf];W[mg];B[jd];W[je];B[jc];W[if]
C[White's move is safe, putting emphasis on creating a solid position in the center, and is not trying very hard to punish Black's group on the upper side.  This makes me think that AlphaGo as White thinks it will win.]
;B[ke];W[kf];B[le];W[lg];B[hc];W[oj];B[ni];W[kh];B[nj];W[jm]
C[White's thick move here strengthens White's connection in the center, while threatening Black's group in the upper right.]
;B[kk];W[ok];B[nk];W[ol];B[ji];W[lj];B[lk];W[jj];B[fl];W[em];B[he];W[ie]
;B[gh];W[hi]
C[With this move White keeps connected.  Black has a weak group on both the left and right, but the right side group is in more immediate danger.]
;B[km];W[kl];B[lm];W[in];B[jo];W[dh]
C[Finally White attacks.  Black is still ahead in territory, and White needs about 20 points in the upper left corner and center combined.]
;B[di];W[eh];B[ei];W[gi];B[fi];W[fh]LB[if:A][gb:B]
C[As with A (move 94), I get the feeling that White is playing conservatively.  With this game move, White could have peeped at B, instead, to put more pressure on Black's upper side group.]
;B[hl];W[jk];B[gb];W[ec];B[cc];W[bj];B[cj];W[cd];B[hd];W[hf]
C[Provided one counts the upper left corner as White's territory, White seems to be ahead.]
(;B[bg];W[ch];B[bh];W[bk];B[bi];W[rn]LB[sp:A]
C[White's extension threatens the ko at A.];B[ro];W[on]LB[ml:A]
C[White's move here is a sente endgame play.  White is looking at the peep at A.]
(;B[om];W[pn];B[nm];W[qn];B[np];W[no]LB[kn:A][mn:B][ml:C]
C[After White's move here, Black still needs to add a stone to the lower side, with the aji of a cut at A, and threatening peeps at B and C.]
;B[sd];W[rd];B[ql];W[rl];B[rc];W[sb];B[cf];W[df]
C[White has answered all of Black's forcing moves.]
(;B[nn]
C[Now it is time for Black to protect the lower side.];W[bf];B[be];W[ce]
;B[bd];W[oo];B[op];W[co];B[ap];W[af]
(;B[db];W[fj]
C[This move kills Black's group.]
(;B[hj];W[ej];B[dl];W[bl];B[ag];W[ai]
C[Black resigns.])
(;B[gk]VW[aa:ss];W[ej];B[hm];W[gm];B[cl];W[bl];B[cm];W[bm];B[hn];W[ho];B[ko]
;W[ck]
C[When Black makes the marked plays in an attempt for a second eye, White will not connect the big lower left group to the center group.  White will easily win the semeai.]
TR[gk][hm]))
(;B[hj];W[db]
C[Black must protect the middle left, but White will take the upper left corner.]
;B[ii];W[hh];B[ki];W[kj];B[li];W[gg]
C[Black A cuts White off in the center, but White's big group is now alive as it stands.]
LB[hj:A];B[cl];W[mk];B[nl];W[ll];B[mo];W[mm];B[ln];W[ml];B[mn];W[bl];B[cm]
;W[bm]
C[When Black attacks (marked), White has the marked play to capture 2 stones with sente.  White easily lives, and is ahead before komi.]
TR[mk][cl]))
(;B[be];W[hr];B[hs];W[op]
C[If Black plays away (marked), White's move here is troublesome.]TR[be]
(;B[nq];W[oo];B[pq];W[ko];B[kn];W[lo];B[mo];W[mn];B[mp];W[nn];B[ln];W[ml]
C[If Black covers and then connects with the marked plays, White can pull the 2 stones out and eventually cut Black off.]
TR[nq][pq]SQ[jp:kp])
(;B[pq];W[nq];B[nr];W[mr]
C[If Black simply connects (marked), White can make use of the aji on the left with this hane.]
TR[pq]
(;B[mq];W[ko];B[kn];W[lo]LB[mp:A]
C[If Black cuts (marked), this becomes big trouble for Black.  Note that White has a forcing move at A, so the White stones are connected and Black's group in the upper right is cut off.]
TR[mq])
(;B[lr];W[mq];B[ms];W[nl];B[ml];W[mn];B[nn];W[mo];B[mm];W[oo];B[lo];W[bd]
C[Black's territory on the lower side has  decreased by about 10 points, so this is good enough for a White win.]
))))
(;B[pn];W[om];B[mm];W[oo];B[nq];W[mo];B[lo];W[kn];B[ln];W[bf]LB[op:A]
C[If Black connects (marked), White can play this local sequence with sente.  Later, White A will be forcing, threatening a step ko in the corner.  Compared to the game, Black has lost a few points.]
TR[pn]))
(;B[db]
C[Black can live in the corner, but ...]VW[aa:si];W[eb];B[bb];W[bd];B[bc]
;W[fa];B[da];W[ka]
C[... White can use the marked forcing move to attack Black on the upper side.  It is difficult for Black to live with both groups.]
TR[fa]))
(;B[cf]VW[aa:ms];W[fc];B[ek];W[fl];B[ef];W[bd];B[gj]LB[ss:A][be:B][cl:C]
C[Black should now make a position on the left side with this sequence instead.

If White plays at A to take the lower right corner, Black has good moves such as B or C to continue on the left side.]
))
(;W[jm]VW[ag:ms];B[en];W[em];B[dm]
C[If White plays away (marked), Black can cut off the corner group with this sequence.]
TR[jm]))
(;B[rq]
C[Black might play this move when trying to kill the group, but ...]VW[ij:ss]
;W[mr];B[lr];W[rr];B[sr];W[np];B[nn];W[qq];B[ro];W[nr];B[mq];W[pr]LB[pp:A][os:B]
C[... Black fails when White has enough room to live, making miai of B and C.]
))
(;W[gr]
C[Locally, White needs to add a move.  I would protect the lower side here, with the feeling that White has gained in this first fight.]
;B[pq];W[cf]
C[After Black secures the lower right territory, Black has a small advantage in territory, while White has some potential on the left side.  So the game is balanced.]
))
(;B[eq]VW[ak:ms];W[hn]TR[er:fr]LB[gr:A][ir:B]
C[Black can cut to capture the marked stones, but White is satisfied to connect up in the center.

Later, White has the option to squeeze with A to strengthen White in the center, or to cut Black off with sente by playing at B.  White controls the left side and center, and this is good for White.]
))
(;B[fn]VW[aj:qs];W[fp];B[gp];W[ho];B[ep];W[ir];B[jq];W[jp];B[lp];W[lo];B[mo]
;W[ln];B[np];W[dl]LB[go:A][ip:B]
C[White's tsuke at A starts a sequence to remove the threat of a cut at B.  Black has a weak group on the left, with relatively strong White groups on each side, so this is bad for Black.]
))
(;W[ir]VW[aj:qs];B[jq];W[jp];B[ip]LB[gr:A][eq:B]
C[When Black cuts here, this is trouble for White.  White will need to back up and play moves at A and B, and Black will be able to control the center fight.]
))
(;B[lp]
C[If Black answers on the right, ...]VW[aj:qs];W[kq];B[lo];W[gr]TR[fo][fq:gq]
C[... then White cuts off the marked group, and Black has no way to use it in an attack.]
))
(;W[gr]VW[aj:qs];B[hq];W[hr];B[ip];W[jq];B[jp]LB[eq:A]
C[If White crawls (marked), Black can build a wall from above, and there is no need for Black to cut at A, which is now an almost worthless point.  This is good for Black.]
TR[gr]))
(;B[gr]
C[It seems natural for Black to cover first, before living in the corner, and so this would be my first idea. ]
VW[aj:qs];W[eq];B[bo];W[ho]LB[fp:A]
C[White's keima is at a vital point, looking at a weakness in Black's shape when White wedges at A.]
(;B[go];W[hn];B[fm];W[dk]
C[This shows White's plan to reduce the lower side, while surrounding the left.  But even so, I think I would have played this way with Black.  If Black can take territory in the lower right, while attacking White on the lower side, the territory will be balanced.]
)
(;B[ip];W[jp];B[io];W[lp]
C[The ladder favors Black, so it might seem a good idea to play the marked cut.  But when White attaches here, it becomes difficult for Black to fight on the lower side and center simultaneously.  If the lower side disappears, Black will be behind in territory, so this is troublesome for Black.]
TR[ip])))
(;W[eq]VW[aj:js];B[fr];W[es];B[bo]
C[If White just connects, Black will descend to cover before living in the corner.  Black has an advantage in this fight.]
TR[eq][fr]))
(;B[qh]VW[ia:ss];W[pj];B[ok];W[ph];B[qg];W[qn]
C[Even if Black plays the pincer (marked), White still has enough room to make life on the side.]
TR[qh]))
(;W[pl]
C[If White hanes here, ...]VW[ia:ss];B[qj];W[ql];B[pj];W[nl];B[op]
C[... Black will cover (marked).  White has no base, and Black is getting profit on both sides, so this is good for Black.]
TR[qj]))
(;B[qi]VW[ia:ss];W[qn];B[op];W[ok]
C[If Black extends on the side, White can still make a base with this sequence.]
TR[qi])
(;B[qm]VW[ia:ss];W[qh]LB[ph:A][oe:B]
C[If Black plays from the lower right, White will extend to here or at A.  Playing at this 3 space distance from Black's wall is often seen in AlphaGo's games, and later it will attack at B.]
))
(;W[rd]VW[ia:ss];B[re];W[rc];B[qf]LB[qc:A][pj:B]
C[The fact that AlphaGo does not play this hanetsugi with White has been cited as a new development that AlphaGo has shown us to change the joseki.

Actually, the difference is that humans would not play the invasion at A in this board position before AlphaGo.

I agree that this marked exchange is bad for White, when the right side is so wide open.  It is meant to be played when Black already has a stone at B.  That is the easy part to understand, while the invasion at A is the move that is difficult to agree with.]
TR[rd:re]))
(;B[nc]VW[ha:ss];W[oc];B[od];W[nb];B[pj]
C[I would suggest this as a normal-looking way for Black to play.])
(;B[od]VW[ha:ss];W[nc];B[nd];W[mc];B[oc];W[ob];B[nb];W[pb];B[lc];W[mb];B[md]
;W[lb];B[pk]LB[kc:A][qi:B]
C[This is a variation of the joseki that I would say is bad for White, but AlphaGo chose it in game 32 and game 50.  The two games differed after this, with White playing at A or B.]
))

