(;GM[1]FF[4]SZ[19]AP[SmartGo:3.1.2]CA[shift_jis]
GN[2018.02.16_AG-KJ-self-play16_annotated]
PW[AlphaGo]
PB[AlphaGo]
EV[AlphaGo selfplay]RO[16]
KM[7.5]
RE[W+R]
RU[Chinese]
AN[Michael Redmond 9P]MU[1]
C[AlphaGo vs. Alphago: Game 16
Commentary by Michael Redmond 9P];B[qd];W[dp]
;B[pq];W[dd];B[fc];W[cf];B[kc];W[qo]LB[po:A][qn:B][qk:C]
C[White 8 is an unusual move in this board position. Human pros would play a kakari at A or B, or split the side with C. ]
(;B[np]LB[pl:A][pk:B][qk:C]
C[B9 is the default move for AlphaGo when White plays a low kakari. In this board position, a human would play a pincer, maybe at A, B, or C. ]
;W[od];B[pf];W[pk]LB[qh:A][qk:B]
C[White plays on the 4th line, increasing the value of White's next move at A. If Black follows with a move on the right side, White will probably play away, in which case W12 becomes a light move that allows White to develop quickly by switching to the left side of the board. Before AlphaGo, pros could play high when expanding a moyo, but would usually stay on the 3rd line within the opponent's sphere of influence, so the more likely move would be a low extension at B, with the aim to quickly settle White's group. Starting with the master series, AG has played high extensions such as W12, and now they are starting to gain popularity among human pros. ]
(;B[cq]LB[qi:A]
C[As always, I have trouble agreeing with, or even finding a reason for this move. In this area, I would play a kakari from the right. Black A is also an important point that I would consider as my first choice in this board position. ]
;W[dq];B[cp];W[cn];B[co];W[do];B[bn];W[cr];B[br];W[bm];B[dr];W[er]
(;B[cm]
C[When Black cuts at 25, the local position will favor White. Black can choose this variation when the left side has a high value. ]
;W[dn];B[bl];W[ds];B[am]LB[ds:A]
C[White has strong thickness when capturing at A, and locally this shape is good for White, compared to other variations of the 3-3 invasion joseki. ]
;W[qh]LB[qe:A][qc:B]
C[W30 is a big move that expands White's potential on the right side and sets up White moves at A or B. ]
;B[pl]
C[B31 is an attachment that can be used to break open White's side. When White plays a hane underneath, there are 2 ladders that Black should have checked out in advance (see var). ]
(;W[qq]
C[W32 is preparing a forcing move in the corner that will change the fight on the side. I suggest that Black should continue on the side now (see var). ]
(;B[qr];W[ol]TR[pp]
C[W34 makes use of the marked forcing move to fight strongly (see var). ]
(;B[qp]LB[pl:A][qr:B][qk:C]
C[When Black has played the attachment at A, and then must back away from the fight with 35, this is already bad for Black. That is my reason for suggesting that Black B should have been played at C. ]
;W[qc]TR[qp]
C[While the right side is still big, it's value has reduced a bit after the marked Black move, just because Black's LR corner is very solid now. ]
(;B[pm]
C[With B37 Black is heading towards a trade giving the UR corner to White and taking profit on the side. The UR corner is the biggest area on the board, so I would say this is bad for Black. ]
;W[pc];B[qk];W[qj];B[rj]LB[pj:A]
C[B41 is a tesuji, and it would be bad for Black to play the atari at A with this move. ]
;W[pj];B[ri];W[om]
(;B[rl]LB[qi:A][on:B]
C[B45 is a good move that takes away all of White's forcing moves. Next Black can play at A or B. ]
;W[og];B[on];W[nn];B[no];W[pn]
C[With the cut at 50, White is preparing to squeeze Black on the side. ]
;B[oo];W[rh];B[ok]LB[ne:A]
C[The ladder favors Black, so it is possible to cut here, but it is hard to say which side will be attacking in the following fight. My first idea for Black would be to jump out at A and see how White responds. ]
;W[nk];B[oj];W[oh];B[oi];W[qi];B[mj];W[ll];B[ln];W[rm]
C[W62 hits a key point in Black's shape, and White can squeeze on the side, or play more strongly for a ko, or if Black avoids the ko both sides will live.]
;B[sk];W[qn];B[ql]
C[Now White can make a ko or live on the side (see var). ]
(;W[sm]
C[W66 allows Black to capture the side, so locally it is a mistake. I think White has a favorable position anyway, so maybe AlphaGo saw no need to play the best move. ]
;B[sl]LB[si:A][ro:B]
C[A and B are now miai, and there is no way for White to win the semeai. ]
;W[rq];B[rp];W[pp];B[rr];W[oq]
C[By forcing with 72, White has created some potential to reduce Black's territory from the left. ]
;B[sq];W[si];B[rn];W[sh];B[qm];W[ne]
C[White lost some points by missing the opportunity to make a ko on the right side, but still has a lead. The territory is close, but Black is weak in the center and the upper side. ]
;B[hq]LB[id:A]
C[With B79, protecting at A is also a big point. Perhaps Black is trying to complicate the game by inviting White to invade on the top, and that would agree with my evaluation of the position. ]
;W[ic];B[ho]LB[ds:A]
C[Even after B81, it will be difficult for Black to attack White on the left. This demonstrates how the ponnuki at A gave White very thick influence here. ]
;W[in];B[gm];W[kj];B[mh];W[il];B[of];W[nf];B[ng];W[qf];B[jm]LB[lk:A][kk:B]
C[Black peeps with 91, looking to cut later with A or B in the center. ]
;W[hn];B[gn];W[go]LB[im:A]
C[W94 is an efficient way for White to stop Black from cutting at A. ];B[fo]
;W[gp];B[nh];W[pg];B[hp];W[fp];B[fq];W[fn];B[fm]LB[im:A]
C[With the sequence to 103, Black might seem to be attacking White on the left, but the real threat is the cut at A. ]
;W[hl]
C[Black cannot kill White's group (see var). ]
(;B[dm];W[eo];B[fr];W[eq]LB[bs:A]
C[It is better for White to force with A before protecting at 108. ];B[jp]
C[With 109 Black surrounds the lower side, and is now about 20 points ahead in territory, before komi. White has potential to attack in the center and the upper side, which is going to be more valuable, so I would say White is still ahead. ]
;W[jg];B[kg];W[jh];B[kh];W[jf];B[le];W[jd];B[kk]
C[B117 hits a weak point in White's connection. ];W[lk];B[lj];W[jk];B[ki]
;W[kl];B[ji]
C[Covering at the left of 123 is dangerous for White (see var). ]
(;W[hi]
C[W124 neatly dodges Black's attack. ]
(;B[kd]
C[B125 makes a living shape for Black's group in the center. ];W[dc]
C[W126 seals off the corner, and White is catching up in territory, even without counting the upper side. ]
;B[ii]
C[White's group in the center is not alive yet (see var). ]
(;W[hj]LB[kn:A][mn:B][ij:C]
C[W128 reinforces White's group in the center. With a combination of moves at A, B, and C, White can make a living shape if the need arises. ]
;B[hh];W[lf];B[mf]LB[kf:A][me:B]
C[Usually B131 should be at A, but since A and B are now miai this move works to connect the Black group.  ]
;W[gd]
C[W132 takes territory on the upper side, consolidating White's lead. The territory now seems fairly close before komi. ]
;B[fh];W[mn];B[mo];W[ko];B[lo]
C[With the forcing sequence to 137, it becomes clear that White can make eyes for this group (see var). ]
(;W[fi]
(;B[ih];W[ei];B[dg];W[bh]LB[kn:A]
C[White lightly dodges Black's attack. White can live at any time by playing at A, so the group in the center is safe. ]
;B[fd];W[fe];B[ge];W[gf];B[he];W[hf]TR[ge:he]
C[W148 does not actually capture the 2  marked Black stones, but White's shape will be fixed as Black struggles to get out of the net. ]
;B[ie];W[je];B[ff];W[ee];B[if]LB[ie:A][ff:B]
C[A and B were both forcing moves that Black didn't really want to play, but they were necessary for Black to break out. ]
;W[gc];B[jn]
C[B155 takes away White's eyes in the center.];W[fg]LB[ci:A]
C[Before connecting at A, White can make some trouble for Black here. ];B[ig]
;W[jc];B[gb];W[hb];B[ef];W[me]
C[W162 cuts Black off on the upper side. ];B[kf];W[ke];B[eg];W[io];B[jo]
;W[ci]
C[W168 saves White's group in the center. ];B[ld];W[mg];B[hc];W[hd];B[id]
;W[hc];B[ha]
C[B175 is a sharp move that creates a ko on the side. ];W[fb];B[fa];W[ga]
;B[qg];W[rg];B[gb];W[jb]
C[Black wants to continue with the ko, but does not have enough ko threats (see var). ]
(;B[eb]
C[Black does not have enough ko threats, so it captures at 183 to live on the side.]
;W[kb];B[ia];W[lb];B[de];W[ce];B[ed];W[sj];B[sn];W[cb]
C[With 192, the endgame starts. White has a secure lead. ];B[gk];W[fk];B[ek]
;W[gl];B[bs];W[hs]
C[W198 is an endgame tesuji, and Black can't capture this stone (see var). ]
(;B[hr];W[fs];B[gr];W[gs];B[is];W[es];B[cg];W[bg];B[fl]LB[em:A][di:B]
C[When Black cuts at 207, Black is reducing White's eye shape, and has a forcing move at A and a wedge at B to cut White off (see var). ]
(;W[bj]LB[di:A]
C[W208 avoids being cut by a Black play at A. ];B[fj];W[gj];B[iq];W[nl];B[db]
;W[ca];B[mm];W[nm]
(;B[da]
C[B217 was a small move and the var for this move shows Black's correct endgame sequence. ]
;W[nj];B[ni];W[df];B[im];W[hm];B[ck];W[dj]
C[Black resigns. White will win by 2.25 stones, or 4.5 points. ])
(;B[cc];W[bc];B[ec];W[cd];B[hk];W[ik];B[fk];W[ij];B[gh];W[gi];B[dj];W[di]
;B[ck]LB[cc:A][ck:B]
C[Black's correct move is to cut at A, after which B is the biggest yose. ]
;W[nj];B[ni];W[ip];B[jr];W[km];B[kn];W[lm];B[jj];W[kk];B[pi];W[ph];B[lg]
;W[mf]LB[nj:A][lm:B]
C[White's forcing move and then B are the two remaining large points, and now only 1 or 2 point moves remain. ]
;B[ak];W[aj];B[em];W[en];B[ja];W[mk];B[li];W[ka];B[da];W[rk];B[rj];W[df]
;B[ee];W[cs];B[bk]
C[White wins by 1.25 stones (2.5 points). ]))
(;W[fj];B[em];W[en];B[di];W[dh];B[dj];W[eh];B[ch];W[gh];B[gg];W[gj];B[fh]
C[This ko is dangerous for White. ]))
(;B[gr];W[fs];B[gs];W[hr];B[gq];W[ip];B[iq];W[jq];B[ir];W[jr];B[is];W[lr]
LB[gr:A][gs:B]
C[If Black tries to capture the White stone with A and then B, White can capture the whole Black group with this sequence. ]
))
(;B[kb];W[ga];B[gi];W[gj];B[gb];W[ka];B[ia];W[ga]
C[White will win this ko. ]))
(;B[ei];W[eh];B[gi];W[fj];B[ih];W[gj];B[gh];W[di];B[ej];W[el]LB[ei:A][ih:B][el:C]
C[If Black plays hane at A, White can fight strongly. Black must protect at B, and finally collapses when White peeps at C. ]
))
(;W[kn];B[km];W[lm];B[jn];W[nl];B[ij];W[jl];B[jo];W[jj]
C[White can make eyes with this sequence. ]))
(;W[hh];B[hj];W[gj];B[gk]
C[White will not be able to live in the center. ]))
(;B[dc];W[cc];B[cb];W[ld];B[kd];W[ke];B[kf];W[je];B[md];W[lf]LB[dc:A][ld:B]
C[Black a is a huge move in the corner, but White has the attack at B ready. Black is not alive yet in the center, so this is bad for Black. ]
))
(;W[ii];B[ij];W[hj];B[hi];W[ih];B[hk];W[gj];B[gk];W[ik];B[jj];W[gl];B[fk]
LB[ii:A][ij:B]
C[If White covers at A, Black's hane at B becomes a strong attack. White cannot escape, and will not be able to live in the center. ]
))
(;B[en];W[gq];B[gr];W[ep];B[fr];W[dm];B[fk];W[cl];B[bm];W[dk]LB[en:A][dm:B][jp:C]
C[When Black captures at A to take away White's eyespace, White can break out with B. Next White can attack at C, and this fight is bad for Black. ]
))
(;W[ro]
C[White makes an eye, threatening to live or make a ko (2 vars for Black's move). ]
(;B[rp];W[sn];B[sl];W[si];B[sp];W[qm];B[so];W[sh];B[sm];W[sj];B[rn];W[jd]
;B[po];W[jc]LB[rp:A][sn:B]
C[If Black covers at A, White can play the key point at B to make a ko. This trade for the upper side gives White a good result. ]
)
(;B[si];W[rq];B[pp];W[rr];B[rp];W[sp];B[pr];W[sm];B[sl];W[rs]LB[si:A][rq:B]
C[If Black lives with A, White can play a sagari at B and live in the corner. This is a big local gain for White. ]
)))
(;B[pn];W[on];B[po];W[rk];B[ql];W[rh]LB[pn:A][ic:B]
C[If Black pulls back at A, White will push once before covering on the side, and White has thick shape on the outside. Black has about 30 pts in the corner, but with the weak Black group on the right, and the threat of White invading at B, this is bad for Black. ]
))
(;B[rc]
C[I would say that the UR corner is the most valuable area on the board at this time, so Black should play this hane (2 vars for White's move). ]
(;W[qe];B[pc];W[pd];B[qb];W[rd];B[qc];W[pe];B[pm]LB[qe:A][pm:B]
C[White's attachment at A is a strong move locally, but the resulting trade is good for Black in this board position. Black has settled the corner with sente, and B becomes a valuable move. ]
)
(;W[pc];B[qg];W[rb];B[ph];W[pm];B[db]LB[pc:A][qg:B]
C[If White pulls back at A, Black can play at B to make miai of the corner and the side. This looks better for Black when compared to the game variation. ]
)))
(;B[pm];W[om];B[pn];W[pp];B[rq];W[on];B[po];W[oo];B[qp];W[op];B[oq];W[rp]
;B[qq];W[rn];B[ql];W[qk];B[rm];W[rk];B[qn];W[qe]LB[ro:A][qc:B]
C[White has a strong position on the outside, and Black's gain on the side is small, and in fact, White can still get a step ko by connecting at A. White's final move in the UR corner can also be at B, and in either case this is good for White. ]
))
(;B[qk];W[pp];B[oq];W[qr];B[pj];W[kq];B[oh]
C[This trade looks about even, and I would play this way with Black. ]))
(;W[ql];B[qm];W[pm];B[ol]LB[ql:A][qm:B]
C[When White plays underneath at A, the tesuji is for Black to cover at B. White cuts once, and now must choose to capture one Black stone or connect on the side (2 vars for White's move). ]
(;W[rm];B[qk];W[qn];B[rl];W[qm];B[pj]
C[When the ladder works, this is good for Black. ])
(;W[qk];B[pn]
C[The ladder works, and this also is good for Black. ])))
(;B[dn];W[cm];B[cs];W[en];B[ne];W[gj];B[nd];W[gf]LB[dn:A][gj:B][gf:C]
C[When Black cuts at A, this becomes what I call a main variation of the AlphaGo joseki for the  3-3 invasion. White B is a shape that AG uses to capture the ladder, and C is how it might expand the moyo on the left. ]
))
(;B[fq];W[cn];B[ip]TR[np]
C[The human move would be to play this sequence to control the lower side, and it seems to work well with the marked stone. ]
))
(;B[pl];W[oc];B[pf];W[op];B[oq];W[np];B[mr]LB[pl:A][np:B][mr:C]
C[In one of the self-played games released as a video on the weiqitv internet channel, AlphaGo played this sequence. Black pincered at A, playing aggressively. AG can play a pincer, but usually just answers at B with Black when White plays a low kakari. Black C is also unusual for both humans and AG, and this was the only one of the 55 self-played games that had this move. ]
))

