(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[utf-8]
GN[RR22_2017.07.11_AlphaGo-AlphaGo-03-annotated-FINAL]
PW[AlphaGo]
PB[AlphaGo]
KM[7.5]
RE[W+Resign]
RU[Chinese]ST[2]MU[1]
C[AlphaGo-AlphaGo Game 3; commentary by Michael Redmond 9p

This game gives me an opportunity to talk a bit about AlphaGo's radical 3-3 invasions, which occur in three corners(!). AlphaGo played an early invasion at the 3-3 in just two of the 60 Master series games, but that was shocking, as it defied the common knowledge of pros that such an early invasion should be bad. In this 50-game series AlphaGo played an early 3-3 invasion about 40 times.

Black plays a big moyo game, and then chases an eyeless White group into Black's moyo, to start a fight that fills the center of the board. 
]
;B[pd];W[dd];B[pp];W[dq];B[co];W[qc]
C[This version of AlphaGo will invade here at any time when there is no urgent fighting going on. As noted earlier, AlphaGo played an early invasion at the 3-3 in just two of the 60 Master series games, but that defied the common knowledge of pros that such an early invasion should be bad. In this 50-game series AlphaGo played an early 3-3 invasion about 40 times. ]
;B[qd]
C[Since AlphaGo invades at the 3-3 but has not stopped playing the star point as a first move in the corner, I assume that it considers the following joseki to be an even result. ]
;W[pc]
C[AlphaGo has its own set of joseki variations, so I will show the main branches in this commentary (two variations added). ]
(;B[nc]
C[Two vars for White's move. ]
(;W[oc];B[od];W[nb]
C[At this point AlphaGo often plays elsewhere, but can continue locally also (3 vars added). ]
(;B[cc]
C[This is the game variation. In the AlphaGo self-played games, there often seems to be a chain reaction that causes repeated invasions to the 3-3 point. This could be linked to my observation that AlphaGo seems to like to invade the corner at a time when the game position is relatively peaceful, and the fact that the joseki (White 6-12 in this case) is simple in itself, thus causing another calm moment in the game and making the next invasion at 13 seem to be a good choice, by AlphaGo's standards. ]
;W[cd];B[dc];W[ed];B[ec];W[fc];B[fb];W[fp]
C[White 20 is a favorite move for this version of AlphaGo. With the White wall in the upper left, this is a position in which a human pro would want to play a pincer on the left side. ]
;B[ci]
C[Black makes a wide extension on the side to put pressure on White in the upper left. ]
;W[ck];B[ei]
C[Black is trying to attack the White wall (see var). ]
(;W[gb]
C[White plays the hane to fix the wall's shape and make some eye space. ]
;B[gc];W[fd];B[hb];W[bc];B[ga];W[cb];B[db];W[da];B[eb];W[ek]
C[The most common move for Black is an attachment in the corner (see var). ]
(;B[cm]TR[bk]
C[Black now has a potential connection underneath (marked). ];W[cp];B[bp]
;W[bq];B[fn]
C[With 35-39, Black has moved out instead of living in the corner, and this allows Black to take the offensive on the left side. ]
;W[cg];B[pj]TR[nc][od:qd]
C[Black 41 makes a moyo on the right, making the marked wall effective. ]
;W[qq]TR[nq]
C[Though White 42 is less of a suprise than 6 and 13 were, this is still a position in which most pros would think that the marked point is White's normal move. ]
;B[qp];W[pq];B[oq];W[or];B[nq];W[nr];B[mq];W[oo];B[op];W[mc];B[nd];W[rc]
C[White 52 and 54 is a big move, giving White good shape in the corner and reducing the value of Black's wall. ]
;B[rp];W[mr];B[kq];W[rq];B[kk]
C[Black 59 expands Black's moyo on the right, while starting to enclose the two White stones on the left. ]
;W[qh]
C[When White invades here, one must remember that Black's wall has no eyes. ]
;B[ph];W[pg];B[oh]
C[With 61 and 63 Black tries to connect to the upper right wall while losing as little territory as possible (see var). ]
(;W[rj]
C[White slides with 64 to reduce Black's right side. ];B[qg];W[rh];B[bg]
;W[bh]
C[Black cannot kill White's group on the right (see var). ]
(;B[qk];W[qf];B[ch];W[bi]
(;B[cf]
C[Black 73 is the strongest move in the local fight, but resulted in Black losing most of its potential in the center, so I don't like this move. ]
;W[dg];B[be];W[di]
C[White 76 is a tesuji to squeeze Black (see var). ]
(;B[df];W[ag];B[bf];W[dh];B[ef]
C[The variation shows how I would play with White. ]
(;W[ba];B[ab];W[gd];B[hd];W[he];B[gf];W[id];B[hc];W[ge];B[bd];W[ih]
C[White has a sizable territorial lead of about 25 points. ];B[pf]
C[Black 93 is a tesuji to set up a squeeze (see var). ]
(;W[rk]
(;B[rg];W[ql]
C[White can connect to the corner, so White's right side group is alive (see var). ]
(;B[gg];W[if];B[ke]
C[White has a territorial lead of about 20 points, so Black must attack strongly in the center. ]
;W[jj];B[hj]
C[Black plays from the outside, pushing White into the remains of Black's moyo. After this, Black is trying to kill the White group in the center. ]
;W[jk];B[bk]
C[Black is trying to play some forcing moves on the left that could change the fight in the center (see var). ]
(;W[kf];B[cl];W[bj];B[dk];W[cj];B[jg];W[jf]
(;B[ep];W[eq];B[gp];W[fo];B[go];W[gq];B[lc];W[mb];B[le]
C[The focus of Black's attack returns to the center. ];W[jh];B[kg];W[ig]
;B[kl];W[jl];B[km];W[kj];B[hl];W[jm];B[jn];W[lg];B[li];W[lj];B[mi];W[fh]
;B[gh];W[ki];B[ii];W[in];B[ej];W[bl];B[kn];W[mj];B[nk];W[ni]
C[This was the final chance for Black to play a peep on the right side (see var). ]
(;B[mh];W[qn]
C[White 146 threatens Black in the upper right (see var). ]
(;B[og];W[gi];B[hi];W[fg];B[ff];W[je];B[om]
C[Black 153 threatens White's group on the right side (see var). ]
(;W[ol];B[kd];W[jd];B[hf]
C[White has only one eye, and must escape towards the lower side. ];W[hk]
C[Black should play the hanging connection now (see var). ]
(;B[gk];W[hm];B[eo];W[fq]
C[Black's group on the left is not completely secure (see var). ]
(;B[bm];W[ak];B[gn];W[gl];B[rm];W[rn];B[ik];W[io]
C[Black still has a potential problem with damezumari on the left (see var). ]
(;B[iq];W[jp];B[jq];W[hp];B[hq];W[fl]
C[Black must be careful how to answer here (see var). ]
(;B[el]
C[The Black group on the left is alive (see var). ]
(;W[kp];B[lp];W[lr];B[lq];W[ml];B[ok];W[nl];B[mk];W[lk];B[ll];W[mo];B[lo]
;W[nn]
C[White finally attacks Black's group in the lower right. Black's weakness on the left is still part of the equation (see var). ]
(;B[pl];W[qm];B[mm];W[nm];B[mn];W[pm];B[qr];W[rr];B[gr];W[fr];B[no];W[np]
;B[mp];W[no];B[gs];W[em]LB[ho:A]
C[Black resigns. With the forcing move at A, White can kill Black's group in the lower right. ]
)
(;B[ip];W[ho];B[jo];W[em];B[fk];W[en]
C[White captures 5 Black stones to connect the center group. ]))
(;W[fk];B[fi];W[gm];B[dn];W[dj];B[dl]
C[Black has a living shape. ]))
(;B[em];W[dl];B[dj];W[fj];B[gm];W[fk];B[hh];W[bo]
C[Black is dead. ]))
(;B[ip];W[hp];B[ho];W[hq];B[jp];W[fl]
C[Black' left side group is in trouble (3 variations).]
(;B[el];W[em];B[fk];W[en]
C[White captures 5 Black stones. ])
(;B[em];W[dl];B[dj];W[fj];B[gm];W[fk];B[hh];W[bo]
C[Black is dead on the left side. ])
(;B[dl];W[en];B[em];W[dn];B[fm];W[gm];B[dj];W[fi];B[fj];W[hh];B[do];W[bo]
C[Black is dead. ])))
(;B[io];W[gl];B[ik];W[gn]LB[ho:A]
C[White threatens a ko at A. ];B[ho];W[il];B[hk];W[fl];B[hn];W[gm];B[im]
;W[jc];B[lb];W[in];B[em];W[dl];B[im];W[fi];B[hh];W[in]
C[White has plenty of ko threats, and is cutting off Black's left side group, so this is good for White. ]
))
(;B[gm];W[hm];B[gl];W[gk];B[gj]
C[2 vars for White's next move. ]
(;W[fk];B[dl];W[hp];B[hn];W[im];B[io];W[ho];B[gn];W[ik];B[hq];W[ip];B[jo]
;W[iq];B[eo];W[fq];B[dn];W[em];B[en];W[dp];B[bm];W[ak];B[bn];W[ap];B[el]
C[Black is alive on the left side. ])
(;W[io];B[il];W[im];B[iq];W[jp];B[jq];W[hp];B[hq]LB[gr:A]
C[Compared to the game, Black has an extra forcing move at A, which strengthens the lower right group. ]
)))
(;W[jc];B[rm];W[rn];B[qm]
C[White dies on the right side. ]))
(;B[io];W[je];B[kd];W[jd];B[hf];W[jc];B[lb];W[kb];B[la];W[nh];B[mg];W[ng]
;B[mf];W[og];B[nj];W[md];B[nf];W[rf];B[of];W[sg]LB[io:A]
C[When Black tries to kill the White group after playing away once at A, White can eventually kill the Black group in the upper right. ]
))
(;B[rm];W[pk];B[oj];W[qm];B[rn];W[sg];B[rf];W[re];B[og];W[sf];B[qe];W[rd]
;B[mh]LB[oj:A][so:B]
C[ As we will see in the game sequence, chasing White around in the center endangers the LR Black group. With the exchange on the right side, Black gets a strong shape at A and an extra eye at B, which will give Black the extra thickness needed to kill White in the center. ]
))
(;B[bl];W[ej];B[fi];W[dl];B[el];W[gk]
C[It is difficult for Black to attack White effectively on the left side. ]
))
(;W[bj];B[ej];W[bl];B[jg];W[ig];B[ji]LB[ej:A]
C[With the extra stone at A, Black can cut White in the center. ]))
(;B[rm];W[qm];B[rn];W[sg];B[rf];W[re];B[og];W[sf];B[qe];W[rd]
C[White can connect on the side. ]))
(;B[rl];W[ql];B[rm];W[og];B[ng];W[of];B[nf];W[pe]LB[ql:A][nh:B]
C[White cuts at A to make some aji and set up a powerful cut next at B. ]
))
(;W[og];B[ng];W[of];B[nf]
C[Black squeezes to make a strong shape in the center. ]))
(;W[gd];B[hd];W[he];B[gf];W[id];B[hc];W[ge];B[bd];W[ih]LB[ba:A][ab:B]
C[This is the same as the game variation, with the A-B exchange omitted. The exchange is not necessary, and can be played at any time, maybe as a ko threat. ]
))
(;B[dh];W[eh];B[dj];W[cj];B[di];W[df];B[bd];W[bb];B[ad];W[ce];B[bf];W[ac]
;B[ba];W[ag];B[ab];W[aa];B[dp];W[cq];B[ab];W[fi]
C[The semeai in the upper left becomes a ko, but since White has local threats this favors White. ]
))
(;B[dg];W[cf];B[bj];W[bf];B[ai];W[ag];B[cj]
C[This is how I would play with Black. White has about 40 pts in territory, while Black has potential in the center. This looks about even to me. ]
))
(;B[qf];W[ql];B[ol];W[qn]
C[White is alive on the right side. ]))
(;W[qj];B[qk];W[qi];B[pk];W[qf];B[og];W[of];B[nf];W[rd];B[bg]TR[qh]
C[This var is an example of Black's basic plan in this fight. Trying to kill the marked invasion would have been unreasonable, so Black plays thickly towards the center and now can fight strongly on the left. ]
))
(;B[cq];W[cr];B[br];W[cp];B[bq];W[dp];B[bp];W[bn];B[cn];W[bm];B[dr];W[er]
;B[cs];W[cg]
C[White has a strong position  to attack on the left side. ]))
(;W[ek];B[fd];W[gc];B[fe];W[gb];B[bd];W[be];B[bc]LB[fd:A]
C[Cutting at A is a strong attack, and this is bad for White. ]))
(;B[mb];W[mc];B[nd];W[lb]LB[rc:A][md:B]
C[Black's double hane is a local loss, so I would suggest that it should be played when the outside Black group is in danger and Black wants to strengthen it with the forcing moves at A or B. ]
)
(;B[rc];W[rb]
(;B[mb];W[rd]
C[(two vars)]
(;B[ob];W[nd];B[mc];W[sc];B[pb];W[qb];B[ne]
C[Black places emphasis on the upper side. ])
(;B[re]
C[(two vars)]
(;W[nd];B[mc];W[sc];B[ne]
C[This variation of the joseki was played in the 1st game of the Ke Jie AlphaGo match. ]
)
(;W[mc];B[nd];W[lb];B[sd];W[ma]
C[Black has a strong wall and extra eyeshape with the ponnuki on the right. ]
)))
(;B[ob]
C[(two vars)]
(;W[pb];B[mb]LB[oa:A][rd:B]
C[In this var White is alive with A or B, and can play away now. ])
(;W[rd];B[mb];W[nd];B[mc];W[sc];B[pb];W[qb];B[ne]
C[In this variation Black is putting emphasis on the upper side. ])))
(;B[mc];W[mb];B[lc]
C[Sometimes AlphaGo will simply extend like this with Black. ]))
(;W[nb];B[mb];W[oc];B[nd];W[od];B[oe];W[ne];B[of]LB[nb:A][mb:B]
C[White's attachment at A has been played in human games, but it is rarely played by AlphaGo. In this variation, the exchange of A for B has strengthened Black and is bad for White, so that is a possible explanation for why AlphaGo does not play this variation. ]
))
(;B[oc];W[ob]
(;B[nb];W[nc];B[od];W[mb];B[pb];W[na];B[qb]
C[This is a basic joseki for humans that is also played by AlphaGo. Black will choose this variation when the upper side is relatively small. ]
)
(;B[nc];W[nb];B[mc];W[mb];B[lc];W[oe];B[od]LB[rd:A]
C[AlphaGo plays this joseki with both sides. This is different from the previous (human) joseki in that White has crawled an extra time on the 2nd line and does not play the hanetsugi at A. ]
))
(;B[od]
C[Two variations for White's move. ]
(;W[oc];B[nc];W[nb]LB[rc:A][mc:B][mb:C]
C[After this Black can play away, or continue here with A, B, or C. ])
(;W[nc];B[oc];W[ob];B[nd];W[mc];B[nb];W[pb];B[lc];W[mb];B[md];W[lb]
C[This is a variation of the joseki that I consider to be good for Black, but AlphaGo plays it sometimes. ]
)))

