(;GM[1]FF[4]SZ[19]AP[SmartGo:3.1.2]CA[utf-8]
GN[Game_002_annotated]
PW[AlphaGo Master]
PB[AlphaGo Zero]
DT[2017-11-09]
PC[The KGS Go Server at http://www.gokgs.com/]
KM[7.5]
RE[B+Resign]
RU[Chinese]
TM[1800.0]OT[3x60 byo-yomi]
AN[Michael Redmond 9P]MU[0]MU[0]MU[0]
C[AlphaGo Zero-AlphaGo Master Game 2
Commentary by Michael Redmond 9P. 

"Although the openings in this series are pretty repetitive, the games themselves vary. So in some, you'll see a half-point game, and in others we'll see Master crash. This game is interesting because it's the first time that Zero has black. Also, later in the game, I get the feeling that Master is acting like it did in the 60-game series earlier this year against top human players, where it thinks its winning and is sort of closing up shop and wrapping up the game. So I wonder whether it mis-read a tsume-go -- actually a 60-move sequence -- in this game." ]
;B[pp];W[pd];B[dp];W[dd];B[qf]TR[cq][qq];W[nc];B[cc];W[dc];B[cd];W[ce];B[be]
;W[cf];B[bf];W[cg];B[bg];W[ch];B[qn];W[fq]TR[bg][ch];B[ip]TR[ch]
C[With the same board position every time, AGZero played the pincer at 19 in 4 games, winning every time. In other games, AGZero chose different pincers. It is natural for Black to be playing some kind of a pincer instead of answering on the left, as White's shape extending to the marked stone reduces the value of the left side. ]
(;W[kq]LB[cq:A][nq:B]
C[With 20, it would be bad for White to take the corner with a play at A (see var). After the joseki in the upper left, the left side is relatively small, compared to other side areas. If White can follow 20 with an extension at B, this will be more valuable than anything that might happen on the left. ]
;B[nq]TR[kq]
C[Black 21 takes away the base for the marked White stone. ];W[dn]
(;B[en]
C[It is correct for Black to attach on the left (see var). ]
(;W[eo]
C[This is a position in which White almost always invades at the 3-3 point (see var), so W24 is an unusual move. White's plan is to sacrifice some stones on the left and build a strong shape on the lower side.]
;B[do];W[fo];B[dm];W[cn];B[cm]
(;W[bo]LB[bn:B][co:A]
C[While White might seem to have options to turn at A or play a sagari at B, W30 is the good shape here (see 2 vars). ]
;B[bm]
(;W[dq]
C[W32 is the tesuji in this shape (see var). ];B[cp];W[cq];B[bp]LB[ip:A][jq:B]
C[
This sequence in the LL corner occured in 8 of the 10 games in which AGZero had Black, with Black's pincer stone at A or B. Locally, this is good for Black, and I would not suggest that people should learn this as a joseki. In this board position the left side is relatively small, and because of that I would say that it is an even game.]
;W[pq]LB[qq:A]
C[In the LR corner, White also had some aji with an invasion at A, so most human players would not play W36 yet. ]
;B[oq];W[qp];B[qo]TR[qm][mq]
C[While leaving potential to make a ko, Master is also looking at the marked forcing moves from outside. ]
(;W[gm]
C[White plays away from the LR corner, but there is some aji that White can use later (see var). ]
;B[fn];W[gn];B[fl]
(;W[gl]
C[The meaning of W44 is to push once with sente and then play on the lower side. However, when this induces Black to extend, it weakens White's position on the upper side, and I would say it is a mistake for White to push here (see var). ]
;B[fk];W[ko]LB[fk:C][in:B][go:A]
C[White tries to surround the lower side, but Black has potential to cut at A or jump at B, and Black can cause trouble here later in the game. Black's strong shape at C is threatening the upper side, and I think this already looks good for Black. ]
;B[hd]TR[ee]
C[AGKeJie and AGZero seem to agree that this 3-space pincer is the correct distance from the UL corner joseki. Black will peep at the marked point next to attack White's wall. ]
;W[gf]LB[ee:A]
C[W48 is a necessary defensive move that removes the threat of Black A.]
;B[kc];W[qe];B[pf];W[ld]TR[qc]
C[W52 splits the two Black groups to attack while protecting against an invasion at the marked point. ]
;B[lc];W[md];B[fc]
(;W[hb]LB[fb:A][id:B]
C[Looking at attachments at A or B, White 56 is a probe (see var). ];B[ee]
;W[fd];B[ed];W[db]
(;B[cb]
C[B61 is a calm move, and AGZero is saying that the corner territory is big. I would be temted to cut, of course (see var). ]
;W[de];B[gb];W[ec];B[fe];W[fb];B[gd];W[ga];B[ib];W[hc];B[ic];W[gc];B[je]
C[In the upper side fight, White has made a living shape, while Black has a strong position on the outside. I call this an even trade. ]
;W[qi];B[ph];W[qm]TR[qp][pq]
C[W76 shows one way that White can make use of the marked stones. AGMaster wants to use some forcing moves to strengthen White's position on the right side, and to set up an attack against the Black group in the upper right. Most of the time AGMaster likes to go for influence on the outside rather than profit in territory.]
(;B[pi]
C[Instead of protecting the corner, AGZero pushes from above to attack (see var). ]
;W[po];B[op];W[pn];B[rp];W[qq];B[rm];W[pm]
(;B[rl]
C[Instead of capturing the corner (see var), Zero plays strongly with 85 to attack White on the outside. ]
;W[rq];B[ro];W[or];B[nr];W[os]
(;B[nn]
C[The corner is a well known life and death problem that will be a ko if Black plays first (see 3 vars). ]
;W[qk];B[qs];W[rs];B[rr]
(;W[sq]LB[qr:C][sr:B][ss:A]
C[W96 is an unusual way to play, but the result is not much different from if White had played at B. If Black takes at A, White will play at B or C to make a ko. ]
;B[ql];W[pl];B[pk];W[pj];B[ok];W[oj];B[rk];W[qj];B[nl]TR[pm]
C[Black captures the marked 5 stones. White's group in the corner is still a ko if Black plays first. ]
;W[nj]TR[je]
C[White is now attacking Black on the right side. It looks like Black can escape, but the marked Black group is not completely alive yet, so there is potential for White to set up a splitting attack. ]
;B[lf]
C[Black plays cautiously from the upper side group. Can it be that AGZero is offering to sacrifice the right side?]
;W[kf];B[ke];W[mf];B[mg];W[nf];B[lg];W[ng];B[rg]
C[Black 115 looks like a clever move that threatens to connect underneath or make life, but will it work?]
(;W[si]
C[W116 kills the Black group. This is the only move that succeeds to do so (see var). ]
(;B[nh]
C[Black has no way to live (see var), and must give up the right side. ]
;W[mh]
(;B[mi]
C[Black sacrifices the side (see var). ];W[oh];B[lh];W[oi]
C[If we assume that the right side is completely White's territory, then White is ahead. It would be interesting to see what Master's value net thought at this point, because it turns out that Zero had ready a way to scoop out the UR corner, and I suspect that Master didn't see it coming. ]
;B[in];W[ho];B[jp]TR[in]
C[The marked jump and B125 cause a lot of trouble for White on the lower side. ]
;W[qr]
C[Both players will be switching back and forth from the side to the corner, and the order of moves is not normal. I would say that the value of the two areas is about the same, making it ok for AG to change around, while it would be strange for a human player to do so. ]
;B[ss];W[lr];B[pr];W[ps];B[jr];W[mk]LB[ol:A]
C[W132 threatens the atari at A. ];B[ns]LB[ol:A][pr:B]
C[If White escapes with A, Black can capture the corner with B, so again this order of moves is strange and mostly pointless, but does not cause any major problem. ]
;W[sr];B[ol];W[hr];B[ir];W[jn]TR[qq]
C[White cannot fight strongly here, and sacrifices the side. In the process White has secured life for the marked corner group, so this is not a complete loss for White. ]
;B[kp];W[lp];B[lo];W[ln];B[mo];W[bq]TR[so]LB[ea:C][mb:A][nb:B][ac:F][jc:I][bn:H][np:G][qr:E][ds:D]
C[W144 is a big move that settles White in the LL corner. White has lost points on the lower side, but has lived in the LR corner and taken this big point. The way AGMaster handled this fight reminds me of the pattern of it's successes in the 60 game Master series, and I get the feeling that it thinks it has a win, so let's try to count the territory. 
If we assume Black A and White B, allowing the right side to completely become White territory, that will be 43 points for White. The area at C is 5 pts, and D is about 10 pts. If we count in the 3 stones that Black can take, E is very small. White has close to 60 points in all. Black has 8 pts at F, about 28 at G, and about 15 with H and I combined, adding up to about 50 points for Black. Black has some potential in the center and left side, but it will not be enough to catch up and pay komi. So, I am thinking that this might be a description in human language of AGMaster's evaluation of this position, but I don't have access to the network data so there is no way to check. In any case, this scenario for a White win was refuted by Black's next move. ]
;B[pb]TR[rg]
C[B145 threatens to connect on the side or live in the corner. Black's marked stone plays an important role in making this work. ]
(;W[pc]
C[With 146 White allows Black to live in the corner. The big question is, what if White had tried to kill? I took a look, and it turned into a rather exciting variation (see var). ]
;B[qc]
(;W[ob]TR[rg]
C[The marked stone is still working to make the difference in this corner fight, and White has no choice but to cut it's losses (see var). ]
;B[rb];W[rd];B[rc];W[qd];B[qa]LB[mb:A][nb:B]
C[Blacks life in the corner is usually worth 20 points, but in this case we have to take note that Black can no longer play at A to force White B. Even counting that in, Black has gained more than 15 points. Looking at the overall position, the game is close in territory, and Black has potential in the center that will be enough to give Black an easy win. ]
;W[ap];B[bn];W[io];B[pr];W[rs];B[fg];W[fm];B[em];W[hi];B[kk];W[ij];B[ji]
;W[gg];B[fh];W[hp];B[lq];W[jj];B[kj];W[jl];B[kl];W[km];B[ia]LB[pb:A]
C[While I doubt the necessity of B175, most of the endgame was well played. Black is leading by around 10 points before komi, and towards the end AGMaster started to throw away points, increasing the margin. The outcome of this game was decided by Black's successful invasion at A. ]
;W[cj];B[ha];W[fd];B[rj];W[ri];B[fc];W[ca];B[ba];W[fd];B[gh];W[hh];B[fc]
;W[gb];B[hg];W[da];B[bc];W[bk];B[co];W[if]
(;B[jk]TR[hg]
C[Black cannot immediately save the marked stone (see var). ]
(;W[jh]LB[jk:A]
C[White cannot answer Black A directly (see var). ];B[il];W[ki];B[kh];W[jm]
;B[ik];W[ig];B[li];W[jf];B[mb];W[mq];B[jo];W[im];B[kn];W[oa];B[pa];W[ko]
;B[bi];W[bh];B[ci];W[di];B[ah];W[dk];B[ao];W[kn];B[mp];W[hs];B[ep];W[ag]
;B[ai];W[le];B[ml];W[ad];B[bd];W[fp];B[lq];W[ab];B[ac];W[lp];B[jq];W[is]
;B[js];W[ls];B[eq];W[er];B[fr];W[cr];B[hq];W[gr];B[gq];W[fs];B[sp];W[og]
;B[mj];W[nk];B[mc];W[ii];B[lk];W[ej];B[eg];W[fj];B[dh];W[ea];B[gk];W[gj]
;B[mr];W[lq];B[kr];W[nb];B[he];W[hf];B[kd];W[nd];B[ps];W[mn];B[mm];W[no]
;B[np];W[sn];B[sm];W[sj];B[sk];W[oo];B[om];W[aj];B[af];W[ma];B[la];W[ka]
;B[lb];W[ef];B[ff];W[fd];B[ge];W[el];B[hk];W[ra];B[sa];W[bj];B[ag];W[sb]
;B[sc];W[jc];B[jb];W[id];B[ie];W[cn];B[dn];W[dg];B[on];W[eh];B[fc];W[or]
;B[os];W[ni];B[sd];W[se];B[sf];W[re];B[aq];W[ar];B[ki];W[hm];B[bb];W[bl]
;B[fd];W[am];B[kg];W[jg];B[fi];W[ei];B[cl];W[rf];B[df];W[lm];B[ll];W[gp]
;B[ms];W[iq];B[hq];W[an];B[ap];W[gq];B[ks];W[lq];B[lr];W[qg];B[kb]
C[Black wins by 3.75 stones (6.5 points)])
(;W[ik];B[il];W[jm];B[ii];W[hj];B[ig]
C[Black escapes with one stone to capture White in the center. ]))
(;B[ig];W[jg];B[ih];W[jh]
C[White captures the Black stones. ]))
(;W[rc];B[rb];W[rd];B[nb];W[mb];B[ob];W[mc];B[sb];W[na];B[qb];W[qd];B[oa]
LB[qb:C][rc:A][rg:B]
C[White A is the usual tesuji to kill Black, but the stone at B comes into play when Black can force with CX to make a living shape. ]
))
(;W[ob];B[pc];W[od]
(;B[qd]LB[qd:A]
C[Black A is the correct move (see var).]
(;W[re];B[rd]LB[rd:B][rg:A]
C[Making use of the stone at A, Black can combine the corner with the aji on the side. With B, Black makes miai of the cut on the 4th line and living in the corner. ]
;W[rb];B[pe];W[qc];B[se];W[rc];B[rf];W[sg]LB[rb:A][si:B]
C[White can kill the corner with A, and after Black takes the 2 stones, White can take away Black's second eye, so White's move at B that killed Black's side group earlier in the game is still working to help White. ]
;B[rh];W[sh];B[sc];W[ra];B[sb];W[pa];B[og];W[qh];B[ll];W[lk];B[kk]LB[og:A][ll:B]
C[After extending the liberties of Black's group, Black cuts at A and attack's White's surrounding group with B. ]
;W[kj];B[kl];W[lj];B[ri];W[rj];B[sk];W[sj];B[jj];W[ki];B[ji];W[kh];B[jh]
;W[kg];B[le]
C[Black manages to surround White, and now a semeai starts. ];W[pg];B[of]
;W[re];B[ml];W[sf];B[qe];W[oc];B[nk];W[mj];B[jf];W[sa]LB[sa:B][re:A]
C[White A was the vital point to reduce Black's liberties, and White plays from the corner with B to set up an advantageous ko for White. ]
;B[jg];W[sd];B[sc];W[sb];B[li];W[sd];B[im];W[re];B[eg];W[se];B[gk]TR[jn][ln][ko]
C[Although the ko fight was favorable for White, it took a lot of moves for White to finish Black off, and meanwhile Black has gained points in the center. Black wins. ]
)
(;W[rd];B[qc]))
(;B[qc];W[re];B[rb];W[sc];B[sb];W[qa];B[pa];W[ra];B[nb];W[mb];B[na];W[oc]
;B[oa];W[mc];B[ma];W[lb];B[la];W[kb];B[ka];W[jb];B[ja];W[id];B[jc];W[ie]
TR[ia]LB[qc:A][nb:B]
C[When Black plays at A, and the usus the tesuji at B to connect on the first line, this is not as good for Black as the main variation. Black is being attacked in the center, and there is a potential ko at the marked point. ]
)))
(;B[ni];W[nm];B[mm];W[mi];B[mj];W[mk];B[lj];W[ol]
C[White captures the cutting stone. This is bad for Black. ]))
(;B[re];W[rd];B[sd];W[rc]
(;B[qh];W[sg];B[sf];W[sh]
C[The Black group is dead. ])
(;B[sh];W[rh];B[sg];W[qh])))
(;W[ri];B[re];W[rd];B[sd];W[rc];B[qh];W[sf];B[sh];W[si];B[se]
C[Black is alive. ]))
(;W[sr]))
(;B[qs]
(;W[rs];B[rr];W[sr];B[ss]LB[sq:A]
C[Black will usually choose to  play this ko. In the case that Black wins the ko and captures at A, Black's territory has good aji. ]
)
(;W[qr];B[rs];W[rr];B[ns]))
(;B[sq];W[sr];B[rs];W[qs];B[qr];W[pr];B[ps]
C[This is another way for Black to make ko. When there is potential for White to make a semeai with one of the surrounding Black groups, this leaves bad aji for Black even if Black wins and fills the ko. ]
)
(;B[rs];W[qs];B[qr];W[rr];B[ps];W[pr];B[qs];W[sq]LB[rs:A][sq:B]
C[While the 2-1 point is said to be a vital point in the corner, it does not work without playing the hane at B first. White is alive. ]
))
(;B[rq];W[rl];B[rn];W[pj];B[oj];W[pk]))
(;B[qq];W[oj]TR[qm]
C[The marked stone makes White's keima possible by protecting against the cut (var for Black's move). ]
(;B[nh]
C[
];W[pm]LB[oj:B][qm:A]
C[The stone at A makes it possible for White to play at B, and White has good shape on the right side. ]
)
(;B[pi];W[pj];B[qj];W[qk];B[rj];W[ri];B[rk];W[rl]TR[qm]
C[The marked stone works to let White capture Black. ])))
(;B[de];W[ec];B[fe];W[fb];B[eg];W[bb];B[bc];W[gc];B[ge];W[di];B[cb];W[ca]
;B[ab];W[fi]LB[de:A][di:B]
C[When Black cuts at A, Black will be losing points in the corner and the upper side, and it is difficult to make a clean kill on the left. In this variation, White can use the forcing move at B to escape. ]
))
(;W[fd];B[gd];W[fb];B[gb];W[ec];B[gc]LB[fd:A]
C[If White simply forces wiyh A, this is not good for White. White must attack the upper side as in the game. ]
))
(;W[hk];B[kp];W[db];B[cb];W[id]TR[fk][en]LB[hk:A][kp:B]
C[White A is  an important point that closes off the center and influences the entire board. Black will control the lower side with B, but then White can expand the moyo on the upper side. I would play this way with White. ]
)
(;W[ko];B[gl]))
(;W[qq];B[ro];W[or];B[nr];W[ns];B[ms];W[ps]
C[White can make a ko. ]))
(;W[bp];B[bn];W[co];B[cq]
C[White is dead.]))
(;W[bn];B[bm];W[bp];B[cp];W[bo];B[bq];W[em];B[fn];W[el];B[gn]TR[cm][bo]
C[Both marked groups have 4 liberties, but White cannot fill a liberty while surrounding the Black group, and Black will win this semeai. ]
)
(;W[co];B[cp];W[bm]
C[This involves a ladder (two vars for Black's move). ]
(;B[em];W[bl];B[bp];W[bo];B[ao];W[bn];B[ck];W[bk];B[eq]LB[bm:A][em:B]
C[When White plays at A, Black B is a calm move. White has a painfully low position on the left, and this is good for Black.]
)
(;B[bl];W[em];B[fn];W[cl]
(;B[dl];W[gn];B[fm];W[el]
C[The ladder favors White, and Black has fallen into the trap. ])
(;B[go];W[dl];B[fp];W[eq];B[ep];W[ir]))))
(;W[cq];B[dq];W[cp];B[do];W[co];B[dm];W[cn];B[fo]LB[cq:A][dq:B]
C[If White invades the corner with A, Black will cover from the right with B. The following joseki would usually be satisfactory for White, but since the left side is relatively small, the direction of play favors Black. ]
;W[ir];B[kp];W[lq];B[mo];W[hq];B[fl]LB[er:B][ir:A]
C[If White continues with the slide at A, Black will play from above, confining White to the side. Later, Black will have a forcing move at B that will allow Black to attack White's groups in the side and corner simultaneously. ]
))
(;B[fp];W[gp];B[fo];W[eq];B[do];W[cr]LB[fp:A]
C[When Black plays  the tsuke at A, White can force Black to make a wall facing the left side, which is not good for Black. ]
))
(;W[cq];B[dq];W[cp];B[do];W[dr];B[er];W[cr];B[eq];W[cn];B[oq]LB[cq:A][dq:B]
C[If White invades the corner at A, Black will cover at B to force White to play towards the left side. While this is a common joseki, it is bad for White in this board position, as the left side is of low value.]
))

