(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]RU[Chinese]SZ[19]KM[7.5]TM[0]OT[1x5 byo-yomi]PW[AlphaGo]PB[AlphaGo]DT[2016-02-29]C[Game 2 - Slaying the DragonCommentary by Fan HuiGo expert analysis by Gu Li and Zhou RuiyangTranslated by Lucas Baker, Teddy Collins, and Thore GraepelLike the first game, this is a blitz with five seconds per move. Since the first 48 moves are identical, please refer to the commentary on the first game for a thorough analysis of the opening.]RE[W+Resign];B[dp];W[pd];B[dc];W[pp];B[nc];W[qf];B[ci];W[fq];B[dn];W[cq];B[dq];W[dr];B[cp];W[br];B[bq];W[cr];B[qn];W[nq];B[pj];W[de];B[fd];W[cc];B[cb];W[cd];B[bb];W[cg];B[qc];W[pc];B[pb];W[qd];B[rb];W[rc];B[qb];W[ql];B[qh];W[ol];B[ne];W[nf];B[mf];W[ng];B[oe];W[pg];B[nj];W[mg];B[lf];W[lg];B[qk];W[rl];B[kg]LB[kf:A]C[Black 49 is the first departure from the previous game. Previously, Black extended at A, so perhaps AlphaGo was dissatisfied with the result in that game.];W[kh];B[jh]C[Now, Black chooses the double hane. If White defends as shown in the variation, the game looks promising for Black.](;W[md]LB[md:52][kg:49][jh:51][kh:50]C[However, White has other plans, disrupting Black’s rhythm with the sharp placement at 52.](;B[ld];W[mc]LB[mc:B][ld:A]C[The exchange of A for B leaves Black hard-pressed to fix up all the weaknesses on the top side.];B[oc];W[li];B[ki];W[lh];B[nl];W[om];B[ji]C[Instead of shoring up the top side directly, Black decides to hang tough and connect on the outside, harassing White on the right while looking for an opportune moment to reinforce the top. ];W[lk];B[ok];W[mk];B[nk];W[lm];B[nm];W[pn]C[Bold though it may be, Black's way of playing is extremely dangerous. At this point, there is still a gap through which Black can break into the open, but the game has already grown painfully difficult. See the variation for White's anticipated continuation.](;B[kl]C[This peep is a probe to test White's intentions.];W[kk]C[White's push on the outside leaves a minor weakness, but is the most uncompromising way of playing.];B[kf]C[In response, Black chooses to risk it all by connecting at 71! Now the top is much stronger, but can Black live with the dragon on the right?];W[rj];B[rk](;W[qi]TR[qi][rj]C[With the marked stones, White seals Black's fate. AlphaGo is capable of killing!];B[mn];W[ko];B[mp];W[kq];B[mq];W[nr];B[kr];W[jr];B[sl];W[qo];B[on];W[pl];B[oo]TR[on][oo]C[The marked stones create some eye shape, but Black is quickly running out of space to live. Carving out the second eye will be a very difficult task.];W[po];B[rm];W[rn](;B[kn]LB[lo:A]C[At this point, Black briefly entertains the notion that everything will be fine. However, this is merely a fantasy, and White will soon put an end to Black's hopes.Actually, Black could also have made a ko starting with A, but the result would have been a Pyrrhic victory. See the variation.];W[ln];B[lo];W[lp];B[mo](;W[mm]LB[km:A]C[Black had hoped for White A, as shown in the variation, but this merciless blow lays bare the harsh reality.Although the following fight looks complicated, the fact is that Black has lost the chance to live. White’s technique may appear suboptimal, but from AlphaGo's perspective, it is the simplest and clearest line.];B[pr];W[pq];B[or];W[oq];B[qm];W[pm];B[sm];W[rp];B[sn];W[ro];B[qq];W[rr];B[mr];W[ks];B[ls];W[lr];B[lq];W[kp];B[kr];W[js];B[qr];W[ns];B[rq];W[sq];B[sr];W[ss];B[qs];W[sp];B[os];W[sr];B[ms];W[iq];B[pk];W[qp];B[np];W[nn]C[The result here is technically ko, but Black has no reasonable means of starting the ko. See the variation for what happens if Black tries.](;B[rh];W[pi];B[ph];W[oi];B[oh];W[ni];B[mj];W[lj];B[sj];W[pf];B[ri];W[qj]C[This is Black's last chance to start the ko, but it will still end in failure. See the variation.](;B[sf];W[rs]C[White kills unconditionally. The remaining moves may be regarded as Black's dying breath.];B[sc];W[sg];B[rf];W[re];B[rg];W[se];B[jn];W[ik];B[ip];W[hq];B[jo];W[jq];B[jk];W[jl];B[jj];W[im];B[gp];W[km];B[gq];W[gr];B[hp];W[fr];B[gm];W[hj];B[hl];W[il]C[Black resigns.AlphaGo’s unparalleled positional judgment and outstanding ability to control the flow of the game are well known. However, some have wondered about whether it can handle life and death situations, even questioned whether such positions might drive AlphaGo berserk. This game should prove to everyone that, indeed, AlphaGo can kill.])(;B[op];W[lr];B[of]C[Black has one local ko threat...];W[og];B[kr];W[si]C[...but so does White.];B[sh];W[lr]C[White retakes, and Black is out of ko threats.]))(;B[op];W[lr];B[rh]C[This is the only plausible threat...];W[no]C[...but White finishes the ko immediately, reaping a huge profit at the bottom.];B[ph];W[fe]C[As long as the upper left does not die, Black will have no way to make up the deficit.]))(;W[km]C[If White simply captures on the outside, Black will live.];B[jn];W[jo];B[np];W[op];B[pi];W[rh];B[ph];W[qg];B[mm];W[jm];B[lq];W[jq];B[mr];W[ks];B[ls]LB[ni:A]C[Black reserves the right to make a second eye with A at any time, so this is a flower-viewing ko for Black. Once Black lives, the territory at the top will prove decisive.]))(;B[lo]C[In fact, Black can create a ko for life starting with this move...];W[eb]C[...but White will create ko threats by targeting the weak points on the top. This peep is a difficult tesuji for Black to handle.];B[fc];W[db];B[ec];W[ln];B[kp];W[jp];B[lq];W[lp]C[Now White starts the ko, with ample ko threats at the top to draw from.];B[rh];W[pi];B[kp];W[fb]C[When White crawls here, Black can no longer contain the situation.]))(;W[sk]C[White must not try to connect underneath.];B[qj]C[Now, this critical forcing move will enable Black to live.];W[ri];B[pl];W[qm];B[mn];W[ko];B[sj];W[si];B[rh];W[rf];B[oi];W[ph];B[qi]C[Black secures an eye in sente.];W[sl];B[mp]C[Because Black already has an eye on the right side, White has no way to kill.]))(;B[mn]C[White believes Black must escape with the kosumi.];W[ko];B[mp];W[hc]C[Now White invades the top, exploiting Black's aji and living easily.];B[gc];W[kf];B[jg];W[me];B[le];W[lc];B[je];W[jd];B[ke];W[hd];B[ff];W[ie];B[mq];W[kq]C[Naturally, this result favors White.]))(;B[kf]C[Black would like to connect here, but this move fails to defend against the push and cut.];W[nd];B[od];W[oc];B[mc];W[ld];B[me];W[ob]C[Black collapses.]))(;W[li]C[Black expects White to defend with the tiger's mouth immediately.];B[ki];W[lh];B[mk];W[ji];B[jg];W[kj];B[ll]C[Now Black can escape on the right side, relying on the forcing moves in the local area to secure the isolated group.];W[jl];B[qp];W[qq];B[po];W[rp];B[qo];W[op];B[nn];W[on];B[oo];W[no];B[mo];W[np];B[om];W[nm];B[pn];W[mn];B[pl];W[on];B[pm];W[hc]C[After Black achieves stability for the group, White will launch a deep invasion at the top. The outcome of this invasion will decide the game.]))