(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[utf-8]
GN[AlphaGo_selfplay_08]
PW[AlphaGo]
PB[AlphaGo]
KM[7.5]
RE[W+Resign]
RU[Chinese]ST[2]MU[1]
C[AlphaGo-AlphaGo Game 8
Commentary by Michael Redmond 9P
Edited by Chris Garlock and Myron Souris

In this game we're going to see two 3-3 invasions; when AlphaGo jumps in to the 3-3, the other AlphaGo does as well. This is something that happens a lot, and I have my own theories about why that might be. We're also going to see the follow-up moves in both of those corners, so we'll see some options about possible follow-ups. And then there's going to be some spectacular fighting inside of Black's moyo. ]
;B[pd];W[dd];B[qp];W[dp];B[np]
C[The Master version also liked this opening with Black (see var). ]
(;W[qc]
C[This position happened in 3 of the self-played games, and White invaded at 6 in each game. AlphaGo seems to think of this as a normal joseki, an alternative to playing a kakari. This is contrary to our existing opening theory, which says that the invasion at 6 is premature and gives Black too much potential on the outside. I believe a top pro with direct access to the policy and value networks might be able to ask the right questions and reach a human understanding of when and how to use these early invasions. ]
;B[qd];W[pc];B[nc];W[oc];B[od];W[nb]
C[Locally, the joseki is not finished, but AlphaGo often plays away at this point (see var). ]
(;B[pj]TR[nd]
C[Black plays on the right side with 13, extending Black's moyo and supporting the wall. Black has left a weakness at the marked point, and later we will see White cutting there. ]
;W[fq]
C[While playing a large point at 14, White reduces Black's potential to expand the moyo towards the left. ]
;B[gp];W[fp]
(;B[cc]TR[gp]
C[ The Ke Jie version usually plays away after playing the marked shoulder hit, perhaps thinking of it as a light kikashi. ]
;W[cd];B[dc]
(;W[ed]LB[nc:A]
C[There is a subtle difference in the order of moves when one compares the UL and UR corners. While Black played the knight's move at A, White now extends at 20. How AlphaGo chooses between these two moves is an interesting mystery, but in this case the resulting shape will be the same. I would have chosen a different joseki with 20. ]
;B[ec];W[fc];B[fb];W[cj];B[ei]
C[With 25 Black is trying to dominate the center (see var). ]
(;W[go]LB[gp:A][fp:B]
C[Locally, White 26 is good shape because it makes A and B a bad exchange for Black. White 26 also radiates thickness towards the lower and left sides, and is an important move in this board position. ]
;B[dg];W[bg];B[rc];W[rb]TR[rb:rc]
C[After playing the marked exchange, it seems natural for Black to continue in the UR corner (see var). ]
(;B[fd];W[gc];B[gb];W[hc];B[fe]LB[fd:A][fe:B][nd:C]
C[With the cut at A and the sequence to B, Black is trying to attack the two White groups. This is an effective follow-up to the corner joseki, and we will find it in many of AlphaGo's games. In fact, White will be cutting at C later in this game. ]
;W[bc];B[bb];W[be];B[ac]TR[ab]
C[Black 39 is an important move, forestalling a White hane at the marked point. ]
;W[nd]
C[White cuts at 40 and the fighting switches to the right. ];B[mc];W[md]
TR[ne]
C[White 42 is an unusual way to play, when the usual move was at the marked point. White plans to push along on the fourth line (see var). ]
(;B[mb];W[kd]
C[White makes good shape with 44, inviting Black to live on the side (see var). ]
(;B[rd]
C[Starting with 45, Black emphasizes the right side and sacrifices the upper side. I agree with this, as the right seems to have potential to become a big moyo for Black. ]
;W[oa];B[ic]
C[Hitting a weak point in White's shape, Black continues with the plan to sacrifice three stones (see var). ]
(;W[lc];B[ne];W[me];B[nf];W[hb];B[mf];W[id]TR[bd]
C[In the trade up to 54, White has almost 25 points on the upper side while Black's moyo has potential to expand. Next, if White connects at the marked point the Black group in the UL corner will not be completely alive (see var). ]
(;B[cf]
C[With the peep at 55, Black sets up to capture a stone in the corner (see var). ]
(;W[qk]TR[pj]
C[White dives into the Black moyo with 56. Locally, this move is too close to the marked Black stone, and is usually thought to be bad shape, but is going to be successful in this case. AlphaGo as White is trying to get as much space as possible on the right side. When I see AlphaGo playing moves like this that are not a part of my usual set of tools, I feel that I can learn a lot from these examples. ]
;B[qj];W[pk];B[ok];W[rj];B[ri];W[ol]TR[ri:rj]
C[The marked exchange gives White's group the extra resilience that it needs to make sabaki (see var). ]
(;B[bi];W[ci];B[bf]TR[bi:ci]
C[Playing the marked exchange before 65 gives White heavy shape and makes 65 more effective. ]
;W[rp]
C[Black has a number of choices in how to answer White's probe at 66, and White's plan will change accordingly (2 vars added). ]
(;B[ro]
C[Black plays the strongest local move with 67. ];W[qo]
C[White 68 is the tesuji here. White offers to sacrifice one stone (see var). ]
(;B[rn]
C[Extending at 69 is the strongest local move. ];W[rq];B[qq];W[qr];B[pr]
;W[rl]TR[qo]
C[As the fight heats up, Black has no way to capture the marked stone. White 74 makes miai of the side and the corner (see var). ]
(;B[oj]
C[Black 75 is necessary to protect the side. ];W[rs]
C[Black has no way to capture the cutting stone (two vars added). ]
(;B[pn]
C[With 77, Black is going to give White profit in the corner and go after White's stones on the side. ]
;W[po];B[qn];W[pq];B[om]
C[This trade was a success for White. ];W[bh];B[cp];W[co];B[bp]LB[cp:A][co:B]
C[Playing the tsuke at A first, and then playing at 85 after White B is an order of moves that I have not seen before. When one looks at the corner alone, it is not a good move. ]
;W[nl];B[oo];W[pp];B[pl];W[bo];B[dq]
C[White can kill the corner, but Black can invade the left side and make use of the bad aji (see var). ]
(;W[af];B[bd];W[do]
C[White plays solidly with 94, allowing Black to live in the corner. ];B[er]
;W[br];B[fr];W[gq];B[cq];W[gr];B[cr];W[ce]TR[ae]
C[White connects at 102 to start an attack in the center. In the case that Black starts a ko by playing at the marked point, Black will have no ko threats near White's strong shape in the LL corner. White has ko threats on the right side, and will be able to win the ko. ]
;B[ij];W[he]LB[hd:A][ie:B]
C[With 104 White again plays a thick move, after playing solidly in the LL corner. This is a valuable move that removes the possibility of a Black cut at A or a clamp at B. White's solid play on the left indicates that White knows it has a lead after White's successful sabaki in the LR corner. ]
;B[fk];W[gi];B[gj];W[fi];B[ej];W[fg];B[kp];W[jl]
C[White 112 puts pressure on the Black group while reducing Black's potential territory in the center. With strong White groups on both sides, White need not worry about Black trying to counter-attack. ]
;B[hi];W[ll];B[mm];W[ko];B[jo];W[jn]
C[The main purpose of White's hane is to reinforce White's group in the center. ]
;B[kn];W[lo];B[in];W[jm];B[lp];W[hk];B[gg];W[eh];B[dh];W[ff];B[hj];W[hm]
;B[io];W[gf]LB[fj:A][di:B][ae:C]
C[White continues to play solidly. White can cut some Black stones off at A or B. The ko at C is still not working for Black, as it will put the Black corner group in danger. ]
;B[kk];W[gm];B[dk];W[el];B[ck];W[bj];B[hh]TR[fj]
C[Black 139 prevents White from playing at the marked point to cut. ];W[kg]
;B[lm];W[kl];B[mj];W[di];B[fj]
C[Black 145 was not necessary for Black's connection, but Black chose this as a good time to ask how White will reply. White might be tempted to play an atari which would be bad, so one might say Black was laying a trap (see var). ]
(;W[ig]
C[White 146 allows Black to capture 2 stones, and White gets good shape in the center. ]
;B[fh];W[eg];B[hg];W[lj];B[if];W[mi]
C[Black's group on the left is still not fully alive. White's plan is to fix its shape in the center while forcing Black to live with two eyes (see var). ]
(;B[lk]
C[Black 153 starts a final fight in the center. Playing safe is not good enough for Black. ]
;W[mk];B[ml];W[nj];B[nk];W[jk];B[mj];W[ap];B[aq];W[mk];B[hf];W[ee];B[mj]
;W[ao];B[bs];W[mk];B[ef];W[df];B[mj];W[jj];B[jg];W[mk];B[nh];W[qi]
C[White 176 is a probe that potentially can help White reduce Black's right side territory (see var). ]
(;B[ni];W[jh];B[jf];W[mj]
C[Black needs to add a move to the right side, but will lose by a few points (see var). ]
(;B[sb];W[rh];B[si];W[oi];B[nm];W[qg]
C[Black can kill this White group but will lose points (see var). ]
(;B[pi];W[ph];B[rf];W[sj]LB[ql:A][og:B][rg:C]
C[Black can't easily kill the White group now. Assuming White can win the ko, White can make a second eye at A, or peep at B to set up an eye with C. ]
;B[qh];W[ra]
C[Since White has a small lead anyway, White can afford to use normal endgame plays as ko threats. ]
;B[ke];W[qi];B[jd];W[jc];B[qh];W[mh];B[ng];W[qi];B[ie];W[ib];B[qh];W[eb]
;B[db];W[qi];B[qb];W[pb];B[qh];W[nr];B[mq];W[qi];B[lf];W[ld];B[qh];W[jq]
;B[jp];W[qi];B[na];W[ma];B[qh];W[mr];B[lr];W[kr];B[ks];W[qi];B[ge];W[gd]
;B[qh];W[ga];B[or]
C[Black 131 is not reasonable, but the fact is, Black already has a hopeless position. ]
;W[qi];B[ji];W[sh]
C[White finally finishes the ko. White is alive now (see var). ]
(;B[ql];W[rg]
C[Black resigns. This game was not a half point, but a full collapse for Black. ]
)
(;B[rm];W[rg];B[pg];W[pf];B[og];W[qf];B[re];W[oe]
C[When Black tries to kill the White group with 1-7, White can cut Black off with 8 and capture the Black group in the corner. ]
))
(;B[ph];W[qh];B[ql];W[rf];B[rk];W[kf];B[ih];W[pi];B[oh];W[pf];B[oe];W[ra]
C[When Black kills White with 1, it becomes apparent that Black's group is also short of eyes, and White can set up a fight to capture with the sequence to 12. Black can win the semeai to capture the White group, but will lose points in the process when playing a lot of stones inside Black's territory. ]
))
(;B[qh];W[mh];B[mg];W[nr];B[mq];W[jq];B[jp];W[mr];B[lr];W[kr];B[ks];W[cm]
C[White will win. ]))
(;B[qh];W[jh];B[jf];W[lg];B[ih];W[oi];B[pi];W[ph];B[nm];W[oh];B[ni];W[ng]
;B[mj];W[mh];B[nj];W[mg]LB[qi:A]
C[This variation is one example of how White can use aji created by the cut at A to reduce Black's territory in the center. White will win by a few points. ]
))
(;B[nh];W[jg];B[ji];W[nj];B[ih];W[ni];B[oi];W[jq];B[jp];W[nr];B[mq];W[mr]
;B[lr];W[kr];B[sb];W[ra];B[ks];W[ap];B[aq];W[ao];B[bs];W[cm]LB[ae:A]
C[This variation shows a relatively peaceful endgame. Black will not have an opportunity to start a ko with A, as that endangers Black's corner. White will win after komi. ]
))
(;W[hg];B[ig];W[gh];B[kf]
C[Playing an atari at White 1 might seem to be a natural move, but Black will counter with 2 and 4 to cut off a White stone in the center. This is bad for White. ]
))
(;W[dr];B[cl]
C[White 1 is the strongest move, and Black cannot live in the corner. When Black invades at 2, the cut and the left side becomes miai. ]
(;W[do];B[dk]LB[bm:A]
C[If White connects at 3, Black can surround White on the left with 4. Later, a Black play at A will create some aji in the corner. This is good for Black]
)
(;W[ej];B[do];W[ep];B[dn];W[bm]TR[dn]
C[When Black cuts and extends at the marked point, White jumping on the second line is a tenacious move. Black must now extend the liberties of the corner group. ]
;B[cm];W[bn];B[cr];W[eq];B[cq]
C[After extending the corner group's liberties Black can win the semeai, so now White must connect on the left. ]
;W[bl];B[er];W[fr];B[ds];W[fj];B[gm]
C[The fight continues in the center of the board. It is hard to compare this with the game and evaluate, but I would say that this is not bad for Black. ]
)))
(;B[qn];W[po];B[pq];W[pn];B[sr];W[rr];B[qm];W[pm];B[ps];W[sp];B[so];W[ql]
C[White wins the semeai. ])
(;B[po];W[qn];B[qm];W[pn];B[pm];W[on];B[rm];W[pq]
C[Black has an advantage in the right side semeai, but is in trouble on the lower side. ]
;B[pp];W[op];B[oq];W[oo];B[pq];W[om];B[pl];W[nq];B[nr];W[mq];B[mr];W[ps]
;B[or];W[lq]
C[I will stop here, but this will not have a happy ending for Black. With the semeai on the right, White's corner group has more liberties than one might expect.]
))
(;B[rr];W[qi];B[sj];W[rk];B[rh];W[oj];B[pi];W[nk]
C[If Black takes the corner with 1, White 2 is a strong attack. Up to 8, this is a good result for White. ]
))
(;B[rq];W[pp];B[qq];W[rn];B[sp];W[rk];B[oj];W[qn]
C[White makes a living shape on the side While reducing Black's corner territory. ]
))
(;B[qq];W[rk];B[oj];W[qo];B[po];W[qn]
C[When Black protects the corner with 1, White can make a comfortable life with 2-6. This is good for White. ]
)
(;B[qo];W[qq];B[pq];W[ro];B[qn];W[qr]
C[When Black extends towards the side with 1, White can scoop out the corner territory up to 6. The White stones on the side still have some potential to escape. I like this for White. ]
))
(;B[nl];W[qi]
C[Black 1 is the natural move for Black to continue attacking, and White 2 is the move that I would play to make sabaki (2 vars for Black's next move). ]
(;B[oj];W[rh];B[rk];W[si];B[rl];W[qf];B[ph];W[qh];B[pg];W[re]
C[White sacrifices 3 stones to live on the right side, and still has some aji in the LR corner. This looks like an even trade. ]
)
(;B[pi];W[nk];B[oj];W[rk];B[qh];W[om];B[ml];W[qn]
C[White lives on the right side. This is good for White. ])))
(;W[bf];B[bd]LB[cf:A][bf:B][ce:C]
C[The A-B exchange makes Black's capture at 2 effective, making the cut at C more direct and limiting White's options for how to defend. ]
))
(;B[kp];W[bd];B[gg];W[ab]
C[White 4 is the vital point in the corner, and Black must fight a ko to live (2 vars). ]
(;B[ca];W[ad];B[db];W[ba]
C[This ko is the correct sequence for Black. ])
(;B[aa];W[ca];B[eb];W[ga];B[da];W[cb];B[fa];W[ha]LB[aa:A][ca:B]
C[When Black captures the one stone at A, White B becomes the vital point and Black's group dies. ]
)))
(;W[id];B[jc];W[jd];B[hd]
C[Black can capture three White stones on the left. ]))
(;B[kb];W[he]LB[ob:A][ib:B]
C[Black is alive with A and B as miai. White has good shape in the center and potential to attack Black on either side, so this is good for White. ]
))
(;B[lc];W[ld];B[kc];W[kd];B[jc];W[ie];B[hb];W[pg]
C[Giving the upper side to Black, White can take the offensive on the right. ]
))
(;B[mb];W[rd];B[re];W[nd];B[mc];W[sc];B[pf]
C[When Black plays the hane at 1, I would expect to see the sequence to 7. Black has spent a move to gain some potential on the upper side, so was it worth it?]
;W[gb];B[gc];W[fd];B[hb];W[ek]
C[I this variation starting with the marked move, Black has played a lot of moves towards the upper side, but maybe that area is not wide enough to merit that. ]
))
(;W[dh];B[gn]
C[Black will control the center now. ]))
(;W[ec];B[eb];W[fb];B[fc];W[ed];B[gb];W[db];B[fa];W[cb]
C[In this position the value of the upper side is small compared to the corner, so I would suggest playing this joseki as good for White. ]
))
(;B[gn]
C[The Master version almost always played this jump to continue from the shoulder hit. Most human players would call this the natural move, although Go Seigen sometimes suggested playing away. ]
))
(;B[mc];W[mb];B[lc];W[pj]
C[If Black simply extends at 1 and 3, where will Alphago play on the right side? I would play at 4, but maybe AlphaGo will play closer to the Black wall and try to attack it. ]
))
(;W[fq];B[gp];W[gq];B[pj];W[nc];B[pf];W[qc];B[pc];W[pb];B[ip]
C[The Master version played this opening with Black in a few games, and the most common human response was White 1. The sequence to 10 occurred in a game against Ke Jie. ]
))

