(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[shift_jis]
GN[RR08-master22_Master-Chen_Yaoye-2_final]
PW[Master]WR[9p]
PB[Chen Yaoye]BR[9p]
DT[2016-12-31]
KM[6.5]
RE[W+R]
TM[60.0]TT[20]
C[Commentary by Michael Redmond 9P
Chen became the youngest player to promote to 9P at 17 when he was awarded with the rank for being a finalist in two world tournaments in 2006. He is still in the top handful of players, and is known for his energetic and innovative play. ]
MU[1];B[pd];W[pp];B[cd];W[dp];B[ic];W[qf];B[nd];W[qc];B[qd];W[rd];B[nq]
C[The Chinese pros seemed to have some foreknowledge of AlphaGo's reappearance as Master, so I would assume that Chen had already seen AlphaGo play away from the corner like this in game 15 against Park Jungwhan and game 20 against Ke Jie, and wanted to see how AlphaGo would handle this with White. ]
;W[qn];B[cn];W[fq];B[pc];W[rb];B[qb];W[rc];B[jp]
C[I think most pros would play to the left side, which is wide open (see var). ]
(;W[ec]
C[Common knowledge is that the keima kakari leads to heavy shape when played against the Chinese opening, and is not good for White. However, AlphaGo continues with a light sabaki sequence that is already changing how we pros think about that. ]
;B[dc]
C[The var for 22 shows the kind of heavy shape that we might expect White to form, and thus the reason that White 20 is supposed to be a bad move. ]
(;W[de];B[dd]
C[White 22 is a sabaki move that has been around for a long time. Black naturally plays strongly at 23. Covering is an overplay, so usually White is trying to switch to the left side (see vars). ]
(;W[id]
C[White 24 just looks good, and one has the feeling that it should work for sabaki. Depending on how Black responds, the way White plays on the left can change (see var). ]
(;B[jd];W[je];B[jc];W[ie];B[ee];W[le];B[lc]
C[Black has good shape in the UL corner, while White has forced Black into a low position on the upper side. I would call this trade about even, but would be happy to play with White. It is important that White has sente and can now take the initiative on the left side. ]
;W[co];B[dn];W[cj]
C[I don't understand why Black did not play the pincer (see var). ]
(;B[fo];W[cg];B[gq];W[gr];B[cq]
C[White cannot cut Black off (see var). ]
(;W[dq];B[bo];W[cp];B[hq];W[fp]
C[Black should simply extend (see var). ]
(;B[bp]LB[bm:A]
C[This was a mistake. By crawling here, Black lost the forcing move at A. ]
;W[bq];B[go];W[bm]
C[White peeps to settle the left side group. ];B[bn];W[cl]LB[gp:A][eo:B]
C[Now Black's wall is eyeless, and Black must be careful of the potential cutting points at A or B. ]
;B[di];W[ci];B[hr];W[gd]LB[ed:A]
C[White 54 is big in territory, and sets up some aji with A for later. ]
;B[er]
C[White cannot connect (see var). ]
(;W[br];B[fr];W[dr];B[qq];W[pq];B[pr];W[qp];B[rr];W[rq];B[qr];W[oq]
C[White tries to force from above and build up the right side (see var). ]
(;B[np];W[or];B[rp];W[ro];B[sq];W[pk];B[qi];W[fm]
C[This is painful for Black (see var). ]
(;B[dl];W[ek];B[cm];W[bl];B[el];W[fl];B[dk];W[dj];B[fk];W[ej];B[gk]LB[en:A][eo:B]
C[For a moment this looks dangerous for White, but since White can cut with A or B, Black has to worry about that and can't continue to attack as he wishes. ]
;W[hm]
C[The usual shape is the diagonal attachment (see var). ]
(;B[il];W[hl];B[hk];W[im]
C[White is almost ready to cut Black and start the semeai (see var). ]
(;B[jm];W[jn]
C[The strongest move is to extend, but then Black will lose the semeai (see var). ]
(;B[jl];W[ho];B[eo];W[kn];B[gp];W[ll];B[jj];W[mo];B[no];W[nn];B[on];W[om]
C[White connects to the right, creating some thickness and preparing to attack Black on the right and in the center. ]
;B[qg];W[pg];B[pf]
C[Black 105~107 is a tesuji for making shape. ];W[rg];B[qh];W[qe];B[pe];W[lj]
;B[qk];W[ql];B[pj];W[rk];B[ok];W[qj];B[pl];W[qk];B[nm];W[mn];B[po];W[nl]
;B[qo];W[lq]
C[Black missed the vital point in the center. ]
(;B[rn];W[gi]LB[ed:A]
C[White 128 attacks Black in the center, protects White's upper side group, and increases the value of the cut at A. ]
;B[hh];W[hi];B[ii];W[ih];B[jh];W[ig];B[jg];W[hg];B[lh];W[oj];B[nh];W[ed]
LB[ee:A]
C[The finishing attack. After the exchange in the center, Black cannot afford to sacrifice the stone at A. ]
;B[df];W[db]
C[Black cannot cover (see var). ]
(;B[cf];W[cb];B[bg];W[bh];B[dg];W[ch];B[fe];W[fg];B[bc];W[hc];B[bb];W[nr]
C[Not only did AlphaGo play sharp moves such as 74, 128, or 140, they were timed perfectly. AlphaGo's ability to control the flow is very evident in this game (end of commentary). ]
;B[pm];W[ol];B[nk];W[ml];B[oo];W[mq];B[nj];W[pi];B[ph];W[ri];B[rf];W[rm]
;B[so];W[re];B[rh];W[si];B[kr];W[lr];B[oi];W[hb];B[pb];W[sf];B[sh];W[sm]
;B[kq];W[pj];B[li];W[mj];B[ke];W[kf];B[kd];W[jf];B[lf];W[mi];B[kg];W[ni]
;B[oh];W[ja];B[kb];W[bf];B[be];W[ag];B[gf];W[gg];B[hj];W[ba];B[ef];W[ck]
;B[em];W[dh];B[ra];W[sg];B[hf];W[ib];B[jb];W[ks];B[js];W[ls];B[kp];W[ko]
;B[lp];W[mp];B[io];W[in];B[hp];W[kj];B[ki];W[kk];B[jk];W[fn];B[en];W[mh]
;B[mg];W[fb];B[ds];W[cs];B[es];W[eq];B[gs];W[qm];B[pn];W[ge];B[ff];W[eg]
;B[ae];W[af];B[fd];W[fc];B[ka];W[ia];B[he];W[hd];B[fj];W[fi];B[km];W[lm]
;B[lo];W[ln];B[hn];W[ps];B[qs];W[os];B[gn];W[an];B[aq];W[ar];B[ab];W[ap]
;B[ao];W[am];B[sb];W[sc];B[qa];W[sa];B[aq];W[sb];B[ap];W[if];B[ce];W[ca]
;B[ep];W[cr];B[ro])
(;B[cb];W[ce];B[cf];W[be];B[bf];W[bd];B[cc];W[bb];B[eb];W[bc];B[da];W[ef]
;B[fe];W[ff]
C[White wins]))
(;B[hh]LB[ed:A]
C[Black 1 strengthens Black in the center, reduces the effectiveness of a White cut at A, and sets up a potential attack against White's upper side group. ]
))
(;B[km];W[ik];B[jl];W[ij];B[gi];W[en];B[eo];W[gl];B[hi];W[do];B[in];W[hn]
;B[io];W[em];B[dm];W[ck]
C[White wins]))
(;B[jl];W[en];B[eo];W[do]
(;B[jm];W[in];B[io];W[jn];B[kn];W[gm];B[jo];W[em];B[dm];W[ck]
C[White wins.])
(;B[gm];W[gl];B[jm];W[in];B[io];W[jn];B[kn];W[em];B[dm];W[gn];B[jo];W[ck]
;B[ho];W[ap]
C[White wins])))
(;B[hl];W[im]
C[Two vars for Black's next move.]
(;B[gm];W[gn];B[fn];W[gl];B[em];W[gm];B[ik];W[km]
C[Black can squeeze to connect his group on the left, but in the process ruins his shape in the center. This is good for White. ]
)
(;B[jl];W[jm]
C[Two vars for Black's next move.]
(;B[km];W[il];B[ik];W[jk];B[kl];W[ij];B[hk];W[hj];B[jj];W[kk];B[gj];W[gi]
;B[hi];W[ii];B[lk];W[kj];B[ji];W[ih];B[ki];W[lj]
C[The ladder favors White. ])
(;B[kl];W[eo];B[en];W[fn];B[km];W[ho];B[gp];W[hn];B[gn];W[gm]
C[White wins the semeai. ]))))
(;B[en]
C[Black really needs to protect here. However, the game is already beginning to look promising for White, and I guess Chen could not bring himself to playing this submissive move. ]
))
(;B[or];W[np];B[mp];W[mq];B[nr];W[mo];B[lp];W[pi]LB[no:A][nn:B]
C[White's forcing moves have created some extra strength which will make it difficult for Black to invade on the right. If Black cuts at A, White will squeeze with B. ]
))
(;W[fr];B[br];W[cr];B[aq]
C[White is not alive. ]))
(;B[go];W[gd];B[ej];W[eg];B[ge];W[hc];B[df];W[dg];B[he];W[hd];B[gg]LB[bm:A]
C[Since Black A is forcing against the LL corner, Black is putting some pressure on the left side White group. White's upper side group is not yet settled, so Black has potential to gain in the center or right side by attacking White's group. ]
))
(;W[bo];B[eq];W[ep];B[fp];W[fr];B[dq];W[bm];B[hq]
C[Black wins.]))
(;B[ch];W[ej];B[fo]
C[Better than the game for Black]))
(;B[hd];W[he];B[ge];W[gd];B[hc];W[ed]LB[ee:A]
C[This variation is from game 48 played against Park Jungwhan. Note that Black cannot cut at A now. White sacrifices stones on the right to gain an advantage on the left. ]
))
(;W[ee];B[ed];W[ce];B[fe];W[ff];B[ge];W[ci]LB[cp:A][bp:B]
C[In this joseki White can make a base on the left side. Black will probably continue with A or B. ]
)
(;W[ed]
C[1 is an overplay. ];B[ee];W[ce];B[bd];W[gd];B[ef]
C[Bad for White]))
(;W[ed];B[df];W[hd];B[id];W[he];B[hc];W[ef];B[eg];W[ff];B[dh];W[ie];B[je]
;W[jf];B[ke]TR[ec]
C[When compared to the actual game this might seem exaggeratedly bad for White. Although it is admittedly oversimplified, it is actually fairly close to the examples that have been used to explain that White 20 (marked) leads to heavy shape. ]
))
(;W[dj];B[dh];W[bp];B[dl];W[fj];B[gm]
C[In this fight Black will try to surround territory on the upper side while chasing the White side group. ]
))

