(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[utf-8]
GN[RR20_2017.07.03_AlphaGo-AlphaGo-02-annotated-FINAL]
PW[AlphaGo]
PB[AlphaGo]
EV[AlphaGo-AlphaGo]RO[2]
DT[2017-07-04]
PC[The KGS Go Server at http://www.gokgs.com/]
KM[7.5]
RE[W+R]
RU[Chinese]ST[2]
AN[Michael Redmond 9P]MU[1]
C[AlphaGo-AlphaGo Game 2; commentary by Michael Redmond 9P];B[pd];W[dd];B[pp]
;W[dp];B[pj];W[nc];B[pf];W[nq];B[pn];W[oo]
C[AlphaGo played this peep in twice in the Master series, but the way White continues has changed now. ]
;B[po];W[pr]
C[In the Master series, I commented that sliding here is the move played by human pros. In the Master series AlphaGo played away both times (see var). ]
(;B[fc];W[cf];B[oc]
C[Black's aim is to give White heavy shape and attack with a pincer/extension (two variations added). ]
(;W[qc]
C[White 16 is an unusual move, but I remember seeing Cho Chikun 9P play this invasion about 10 years ago. White is trying to reduce the value of White's outside stone by creating aji in the corner (two variations added). ]
(;B[nb]TR[nd]
C[Black's hane underneath was the game move. Compared to the hane on top (marked) this move gives White less space in the corner (see var). ]
(;W[rf]
C[There is a weakness in Black's shape when Black tries to cut off the corner stone (see var). ]
(;B[rg]
C[Black sacrifices one stone to get the corner. ];W[qg];B[re];W[rh];B[rj]
;W[fq]
C[It is awkward for Black to make a clean kill, so White just leaves the whole right side (see 2 vars). ]
(;B[fe]
C[It is difficult to cleanly kill White on the right, so Black expands the upper side instead. ]
;W[mb]
C[White's hane is the tesuji to increase White's potential in the area. ]
;B[mc];W[nd];B[lb];W[ec];B[fb];W[og]
C[How does Black add a move to the upper side? (see var). ]
(;B[ma];W[oi];B[oj];W[dk]
C[Again White plays away. Can Black find a strong attack against White group on the right side? ]
;B[dg];W[cg];B[dh];W[ch];B[di];W[bj];B[lg]
C[Black attacks while expanding the upper side. ];W[mi];B[ek];W[el];B[fl]
;W[em];B[nh]
C[Black cuts White into two groups. ];W[ni];B[ph];W[pg];B[oh];W[of];B[qf]
;W[pi];B[qi];W[qh];B[mh];W[sg];B[qd];W[li];B[se];W[le];B[md]
C[This is a position in which I would probably attempt to live, while AlphaGo sacrificed the group and took profit on the outside (see var). ]
(;W[si];B[ri]TR[ri:si]
C[The marked exchange must seem to be a strange move for White, in that White started out having an eye with sente, but now has allowed Black to reduce it to an eye with gote. White is actually planning to sacrifice the right side group, and this exchange has created some bad aji inside Black's right side territory that White will exploit later in the game. ]
;W[jh];B[kf];W[if];B[ke];W[gg]
C[I would never have thought of playing this way for White, sacrificing the right side group. White is actually putting a lot of pressure on Black's stones on the left side and reducing Black's upper side, so White's play here is very effective. ]
;B[fk];W[dj];B[il];W[ef]
C[Black wants to surround the upper side now (see var). ]
(;B[fm];W[id];B[hi];W[kd];B[me]
C[Black is connected with this move (see var). ]
(;W[ll]
C[White's stones in the center are not settled, so this move defends while attacking. White is also looking at Black's weak shape on the right side. ]
;B[gp];W[en]
C[With this move, White's LL corner territory is secure for now. I think Black's next move was heavy (see var). ]
(;B[fn]
C[Black has not surrounded any space with 85, and therefore does not have eyes yet. ]
;W[hc];B[ig]TR[hi]
C[Black's tsuke hits a weak point in White's shape. ];W[ih];B[hf];W[hg];B[ie]
;W[he];B[jf];W[gf]TR[ge]
C[Black has a potential ko (marked) but not enough ko threats to make it effective. Black now plays a very tight move (see var). ]
(;B[ol]TR[qk:rk]
C[With 95 Black is dealing with the bad aji (marked). ];W[qq];B[cc]TR[ge]
C[White cannot allow Black to connect on the upper side (see var). The potential of the marked cut has a connection with some of the variations of this fight in the UL corner.]
(;W[eb];B[cd];W[de];B[db]
C[Black is alive (see var). ]
(;W[ea];B[be];W[iq]
C[White continues to attack Black in the center. ];B[km];W[lm];B[jo];W[gq]
;B[cq]
C[Black invasion of the corner is a probe, not a serious attempt to live. ]
;W[rk]
C[White tries to create some aji on the right side.];B[ro]
C[There is some aji on the right side, shown in a variation.]
(;W[hp]
C[It is dangerous for Black to leave the center as it is. ];B[ho];W[go];B[oq]
;W[or];B[np]LB[lo:A]
C[Creating the connection at A, Black reinforces the center group and the right side. ]
;W[hn];B[hm];W[dq]
C[Black cannot live in the corner, but I suggest Black should continue here to create a weakness in White's shape (see var). ]
(;B[eo];W[do];B[mq];W[nr];B[io];W[fi];B[dr];W[er]TR[do:eo]
C[After playing the 121-122 exchange (marked), Black has less potential in the corner than before (see var). ]
(;B[ej];W[gn];B[in];W[fo];B[mo]TR[rk]
C[Black is still dealing with the aji created by the marked White stone, strengthening the right side while protecting the Black group in the center, threatening White's group in the center, and reducing White's potential on the lower side.]
;W[lp];B[mp]TR[hh]
C[With 133 and 135 Black is threatening the White group with the marked cut in the center (see var). ]
(;W[gi];B[hj];W[lo]
C[White 138 protects the White group by preparing to connect to the lower side,  while cutting off the Black group in the center. ]
;B[hh];W[if];B[gh];W[fh];B[hf];W[nl];B[nk];W[if];B[fg];W[om];B[pl];W[eg]
;B[hf]TR[ge]
C[In this ko fight, Black is still attacking White in the center and hoping to start a ko by playing at the marked point. However, Black does not have enough ko threats to succeed with that plan. ]
;W[pe];B[qe];W[if];B[gm];W[fp];B[hf];W[pm];B[qm];W[nm];B[ql];W[kn]TR[ge]
C[With 162, White has connected to the lower side. Black's center group is not alive yet, so Black cannot cut at the marked point. ]
;B[kl];W[kk];B[jk];W[jm];B[jl];W[jn]TR[ge]
C[By taking away Black's eyes in the center, White makes the ko with the marked cut too dangerous for Black to play. ]
;B[ff]TR[fh:fi][gi]
C[With 169, Black cannot capture the marked White stones but sets up a squeeze to make life in the center. ]
;W[ge]
C[A peaceful endgame is not good enough for Black (see var). ]
(;B[mr]TR[kq][rr]
C[Black 171 makes miai of the two marked points. ];W[im];B[gd];W[hd];B[eh]
;W[fd];B[ed];W[ee];B[fd];W[fa];B[kq];W[kp];B[dl];W[cl];B[rr]
C[Black 185 does not kill the corner outright, but it will be a decisive ko fight. ]
;W[gb]
C[White threatens to kill Black's group in the center. ];B[kj];W[lj];B[ki]
;W[lh];B[mf];W[kh];B[hk]
C[Black is alive. ];W[rq];B[sp];W[sq];B[ns];W[rs];B[qs];W[sr];B[ss];W[bb]
;B[cb];W[rs];B[bp];W[br];B[ss];W[qo]
C[At this point Black chose the most complicated variation, so what happens if Black plays simply? (see var)]
(;B[rs]
C[Black finishes the ko in the corner, but now trouble brews on the right side. ]
;W[op];B[on];W[sj];B[qj];W[rn];B[qn];W[rp];B[qp];W[so];B[jq];W[jp];B[qo]
C[White can connect the two dead groups and the question is what happens with the semeai? (see var)]
(;W[sl];B[rm];W[sm]TR[rl]
C[White connects with a ko, leaving the marked point open. Since White has a big eye and Black's eye will be small, inside liberties are advantageous for White. ]
;B[sn];W[pq];B[no];W[rn];B[sf]
C[White cannot finish the ko yet (see var).  ]
(;W[nj]
C[White kills the Black group. ];B[sn];W[da];B[ca]
C[Black will lose if White captures the UL corner. ];W[rn];B[mk];W[lk];B[sn]
;W[bc];B[ab];W[rn];B[lq];W[sn];B[ir];W[hr];B[is];W[ms];B[ls];W[kr];B[jr]
;W[ks];B[os];W[ps];B[ms];W[nn];B[oq];W[op];B[nf];W[sp];B[mn];W[ln];B[rl]
;W[sk];B[oe];W[sh];B[oo];W[ml];B[ng];W[mj];B[qk];W[ok];B[nk];W[mk];B[oq]
;W[mm];B[rg];W[op];B[rf];W[nk];B[oq];W[ba];B[bd];W[op];B[ip];W[hq];B[oq]
;W[bf]
C[White does not capture the 4 Black stones in the corner, as White is saving that for the final ko (see var). ]
(;B[qr];W[ae]
C[White kills the corner, and now the game is close before komi. ];B[cr]
;W[bo];B[ei];W[ii];B[ij];W[ci];B[jd];W[jc];B[aa];W[ac];B[jb];W[je];B[co]
;W[bn];B[jd];W[if];B[fj];W[gc];B[cm];W[cn];B[hf];W[kc];B[ib];W[ic]
C[W+~3.25 stones (~6.5 pts)])
(;B[ae];W[op];B[dn];W[hs];B[oq];W[qr];B[rs];W[pk];B[rr];W[lr];B[ss];W[op]
;B[js];W[kr];B[oq];W[qs];B[rs];W[lr];B[rr];W[op];B[ks];W[lr];B[oq];W[ss]
;B[rr];W[op]LB[dc:A]
C[White can use the local threats to win. Black A is not big enough to be a valid ko threat. ]
))
(;W[sn];B[lk];W[mk];B[nj];W[mj];B[ir]
C[Black has two eyes, and White is dead. ]))
(;W[rm];B[rl];W[sl];B[sf]TR[sh][sk][sm:sn][sp]LB[rm:A]
C[White must play to connect all the marked points, and White A has filled one of White's liberties compared to the game sequence. ]
))
(;B[rn];W[rs];B[jq];W[jp];B[ss];W[qp];B[qn];W[rs];B[cr];W[bo];B[ss];W[bc]
;B[ab];W[rs]
C[Both sides have a large number of ko threats, but it looks like Black will eventually lose the ko and the game (the following lengthy sequence is my analysis of the ko fight). ]
;B[mn];W[ln];B[ss];W[da];B[ca];W[rs];B[cj];W[ck];B[ss];W[bd];B[ba];W[rs]
;B[co];W[cn];B[ss];W[ce];B[ac];W[rs];B[dn];W[dm];B[ss];W[bf];B[ad];W[rs]
;B[bs];W[ar];B[ss];W[qj];B[qk];W[rs];B[lk];W[mk];B[ss];W[sj];B[qj];W[rs]
;B[nj];W[mj];B[ss];W[mg];B[ng];W[rs];B[mm];W[ml];B[ss];W[nf];B[mg];W[rs]
;B[ds];W[ap];B[ss];W[ij];B[ii];W[rs];B[bq];W[aq];B[ss];W[od];B[pc];W[rs]
;B[bn];W[cp];B[ss];W[ji];B[jj];W[rs]
(;B[ao];W[an];B[ss];W[op];B[on];W[rs];B[am];W[qr];B[ao];W[pq];B[nn];W[an]
LB[dc:A][gj:B]
C[White wins. If Black uses the ko threat at A, White will next use the ko threat at B .]
)
(;B[an];W[es];B[ss];W[op];B[on];W[rs];B[ao];W[cs];B[ss];W[pq];B[nn];W[rs]
LB[dc:A][gj:B]
C[White wins the ko. If Black uses the ko threat at A, White will next use the ko threat at B.]
)))
(;B[im];W[kq];B[gd];W[hd];B[eh];W[fd];B[ed];W[ee];B[fd];W[gb];B[kj];W[lj]
;B[ki];W[lh];B[mf];W[kh];B[gj];W[fa];B[rp];W[lr]
C[This seems to be fairly close before komi, so Black cannot win. ]))
(;W[ei];B[hh];W[if];B[fh];W[gh];B[gi];W[eh];B[eg];W[fg];B[fj];W[fh];B[hf]
LB[ge:B][ei:A]
C[Not only is the White center group in danger, but White A has allowed Black to create damezumari for White and make the cut at B a strong threat. ]
))
(;B[cp];W[bo];B[co];W[cn];B[bp];W[br];B[bn];W[bm];B[ao];W[cr];B[cm];W[bl]
LB[fp:A]
C[Black A is not forcing. ]))
(;B[dr];W[er];B[cp];W[bo];B[co];W[bn];B[cn];W[bm];B[io]
C[Black's idea is to play this connection with sente (two vars for White's move). ]
(;W[fi];B[eo];W[do];B[fp];W[dn];B[ej]LB[fp:A]
C[Black A captures 2 stones with sente, settling the Black group. ])
(;W[gn];B[in];W[fo];B[fi]LB[hh:A]
C[Black has a living shape in the center and is threatening to cut at A next. ]
)))
(;W[ql];B[pl];W[sj];B[qj];W[qm];B[on]
C[For now, Black is going to win the semeai on the right, but I cannot say how this possibility of a semeai might interact with fighting in the center, and that is what White is aiming at here. ]
))
(;W[be];B[ea];W[ge];B[bb];W[ac];B[ab];W[ca];B[da];W[ba];B[hb];W[ib];B[ha]
;W[gc];B[gb];W[fa];B[ia]
C[In this var Black has escaped by connecting to the right. ]))
(;W[cd];B[dc];W[ed];B[eb]
C[Black is alive. ]))
(;B[qq];W[qk];B[qj];W[pl];B[rl];W[nl];B[ql]
C[White can make use of Black's bad shape on the right side to get some extra stones in the center. ]
))
(;B[io]
C[Black has good shape and some space for eyes. All of Black's stones are connected, as the following moves ofthis var will show.]
;W[go];B[fo];W[fn];B[gn]
C[This sequence is to show that White cannot cut Black off here.]))
(;W[mf];B[nf];W[ng];B[mg];W[ne];B[ld]
C[Black is connected. ]))
(;B[id];W[in]
C[White will attack the Black group to profit on the lower side. ]))
(;W[me]
C[Three variations for Black's next move. ]
(;B[kf];W[sf];B[si];W[ri];B[qj];W[od];B[pc];W[mg]TR[kf]
C[Black's kosumi was bad shape. White is alive now (two vars for Black's next move). ]
(;B[lh];W[ng]
C[White has two eyes. ])
(;B[ng];W[lh];B[mf];W[nf];B[mg];W[kg];B[lf];W[jf]
C[A ladder. ]))
(;B[ne];W[kf];B[kg];W[jg];B[kh];W[mg];B[ng];W[nf];B[mf];W[lf];B[mg];W[jf]
;B[ki];W[oe]LB[ne:A][mg:B]
C[By cutting at A Black is trying to reduce White's eye space. White B is a tesuji that fixes White's shape and fills Black's liberties. White has an eye on the right, and enough room to make a second eye in the center. ]
)
(;B[kg];W[jf];B[jg];W[od];B[pc];W[jd]LB[kg:A]
C[Extending at A is Black's strongest move. My guess is that AlphaGo discarded this variation as too dangerous for White. ]
)))
(;B[md];W[oi];B[oj];W[ob];B[ma];W[qd];B[qe];W[od];B[pc];W[pb];B[pe];W[rb]
TR[md]
C[When Black pushes (marked), White can still live in the corner. ]))
(;B[ph];W[mb]
C[White still has a lot of aji here, and when White has a better position on the rest of the board, sacrificing the whole right side is also an option (two vars for Black's move). ]
(;B[mc];W[nd];B[lb];W[qe];B[qf];W[ob];B[ma];W[qd];B[sf];W[pe]TR[ph][fq]
C[White breaks open the corner. The marked exchange has become a big gain for White, and White has a good overall position.]
)
(;B[ob];W[qe];B[qf];W[sg];B[qd];W[se];B[rd];W[pg];B[og];W[of];B[pe];W[oh]
;B[ng];W[pi];B[oi];W[qh];B[ni];W[qj];B[qk];W[ri]TR[mb]
C[After the marked forcing move White will switch to the upper side, but still has the ko shown here to play later. ]
))
(;B[pg];W[mb];B[ob];W[qe];B[qf];W[sg];B[qd];W[ph];B[qi];W[qh];B[oh];W[ri]
;B[si];W[pi];B[oi];W[qj];B[qk];W[rk]
C[White still has a ko on the right side. ]))
(;B[rd];W[qd];B[qe];W[pb];B[re];W[ob];B[nd];W[mc];B[mb];W[lc];B[lb];W[kc]
;B[kb];W[jc];B[jb];W[ic];B[ib];W[hc];B[hb];W[gc];B[gb];W[fd];B[ec];W[ed]
TR[pb]
C[In this var White's peep (marked) becomes a double threat and White can force Black to a low position. The corner dies, but this is good for White. ]
))
(;W[re];B[rf];W[qe];B[qf];W[pb];B[ob];W[rb];B[fe]
C[In this var White's corner is cramped and needs an extra move to live. Black gets sente to expand the upper side. ]
))
(;B[ob];W[id];B[rf];W[ec];B[fd];W[ff]TR[ob]
C[Black's sagari (marked) reduces White's potential in the corner but has a limited effect on the upper side. If Black adds a move to secure the corner as in this var, White can take the initiative on the upper side. ]
)
(;B[nd];W[re];B[rf];W[qe];B[qf];W[ob];B[nb];W[pb];B[mc];W[ge]TR[nd]
C[When Black plays the hane on top (marked), White can easily live in the corner. Black has a nice thick shape, but maybe is a bit slow. ]
))
(;W[nd];B[kc];W[ke];B[id]
C[White has heavy shape, and Black can attack while surrounding the upper side. ]
)
(;W[jd];B[nd];W[ec];B[fd];W[hd];B[fg]
C[In this fight, White tries to take the initiative to attack. This kind of sequence has been played in pro games, so one might assume it is about even, but it is worth noting that Black has a big territory in the UR corner, and it is not clear that White can take the offensive on the upper side. I think that this favors Black. ]
))
(;B[qq];W[kq]TR[oo:po]
C[It can be argued that the marked exchange is profitable for White in that it gives White some extra strength towards the center. ]
))

