(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]CA[shift_jis]
GN[master04_Xie_Erhao]
PW[Magist]WR[9p]
PB[Xie Erhao]BR[9p]
DT[2016-12-29]
KM[6.5]
RE[W+R]
TM[60.0]
C[This commentary by Michael Redmond 9P accompanies his latest video commentary on the AGA's YouTube channel, available here: https://youtu.be/3jGkC9jeU5s

Xie Erhao was born in 1998, and he went to the semifinals in the Mlily cup in 2012. He has since been in the top group of Chinese players, and is a player worth watching in the next few years. I will start with an example of the Kobayashi Fuseki. ]
TT[20]MU[1]
(;B[qd]
C[Why did I put in variations for the Kobayashi opening? The opening in this game resembles the Kobayashi opening, and the general knowledge that I explained in those variations should be valid for it. However, Master plays the move that we thought to be bad, and goes ahead and makes it work. ]
;W[pp];B[cd];W[dp];B[cn];W[fq];B[qn];W[nq];B[dj]
C[The left side of the board resembles the Kobayashi Fuseki. The common knowledge is that White should play a large knight or two space high kakari (see vars), but AlphaGo apparently doesn't agree. ]
(;W[ed]
C[The game move. ];B[hd]
C[This fight will be advantageous for Black, with the Black left side stone joining in to attack White (see var). ]
(;W[dg]TR[dj]
C[With the marked Black stone on the left side, White 12 is unheard of in pro games. It seems to be an unreasonable move, so it is disturbing to see AlphaGo do this and then go on to win against a top pro. ]
;B[ee];W[fe];B[ef];W[dd];B[ce];W[cc];B[bc]TR[dj]
C[With a good joseki dictionary, one might find that Black's hane is supposed to be an overplay, but that is not true when Black has the extra marked stone (see var). ]
(;W[bb];B[fd];W[db];B[cf]
C[Locally, this is a good result for Black. However, it can be argued that since Black started off with a local advantage, White could not hope for an even result in any case, so maybe this is not so bad for White. The final verdict remains unknown to me, and I will have an opinion only after several practice games, maybe. ]
;W[oc];B[ld];W[pe];B[pd];W[od];B[oe]
C[White usually plays a tsuke on the 4th line now (see var). ]
(;W[qe]LB[qi:A]
C[AlphaGo departs from the well-trodden path with 30. This move has been played with a White stone in the vicinity of A, but is considered an overplay without that extra stone. AlphaGo plays aggressively when it judges itself to be behind, so that may be the case here. ]
;B[re];W[rf];B[rd];W[ne];B[of];W[pg];B[nf];W[me]
C[Black should jump in the corner (see var). ]
(;B[pc];W[ob]TR[pc]
C[Black 39 (marked) is bad because Black's corner is short of liberties, and Black cannot attack White on the right to make a semeai (see var). ]
(;B[pb]LB[rb:A]
C[Black 41 was forced. Now White has some space on the upper side, and can molest Black's corner with A later in the game. Black's mistake at 39 gave White the advantage in this fight. ]
;W[le]TR[pe:qe]
C[Now that Black has protected the corner with 41, the value of the marked stones is reduced (see var). ]
(;B[jd];W[qi]
C[White can settle both side groups. ];B[nh];W[lc];B[qk];W[pj];B[pk];W[nj]
;B[lg];W[kd];B[kc];W[ke];B[lb];W[mc];B[lj];W[ok];B[oi];W[oj];B[on];W[pm]
;B[qm];W[pl];B[ql];W[nm];B[om];W[ol];B[pn];W[rp]
C[White's sequence from 62 to 70 is almost a textbook example of how to attack by taking away the base of an opponent's group. White is pulling ahead in territory. ]
;B[nn];W[mm];B[mn];W[km];B[jg];W[kk];B[mq]
C[Black's tsuke is a tesuji (see var). ]
(;W[np];B[mp];W[kj]LB[if:A]
C[Pushing at 80, White strengthens White's center group, threatens to attack at A, and reduces Black's potential in the center and left side. ]
;B[mr];W[nr];B[iq];W[jc];B[ic];W[kb];B[if];W[bp]
C[I seem to hear AlphaGo declaring victory. White has a lead in territory, and Black does not have enough space to catch up. ]
;B[bo]LB[en:A]
C[Black realizes that he is behind, and declines to play the more reasonable move at A. ]
;W[dk]
C[White 90 starts a middle game joseki that reduces Black's left side and avoids any dangerous variations. ]
;B[ck];W[cl];B[dl];W[ek];B[el];W[cj];B[bk];W[fl];B[bl];W[fk];B[di];W[fc]
;B[gd];W[fi]
C[White is winning. End of commentary.];B[bq];W[cq];B[ap];W[hr];B[ir];W[hq]
;B[io];W[ip];B[jp];W[hp];B[jo];W[eh];B[ch];W[li];B[lh];W[mi];B[cr];W[dr]
;B[cp];W[dq];B[ro];W[qq];B[gh];W[gi];B[jb];W[kc];B[hi];W[hj];B[hh];W[bd]
;B[be];W[ac];B[ns];W[os];B[ms];W[pr];B[hs];W[gs];B[is];W[qg];B[oa];W[br]
;B[ar];W[bs];B[ij];W[ik];B[hk];W[gj];B[rj];W[ii];B[ih];W[jj];B[do];W[ri]
;B[fp];W[fr];B[kn];W[jm];B[fm];W[gm];B[fn];W[gb];B[hb];W[ja];B[ma];W[nb]
;B[na];W[ib];B[ha];W[je];B[ie];W[la];B[pa];W[mb];B[ep];W[cg];B[bg];W[dh]
;B[ci];W[gn];B[go];W[ho];B[in];W[gp];B[fo];W[im];B[ae];W[qj];B[rk];W[rb]
;B[rc];W[qb];B[sb];W[ga];B[ra];W[kh];B[kg];W[jh];B[qo];W[qp];B[sg];W[sh]
;B[sf];W[rg];B[se];W[ia];B[hc];W[ln];B[lo];W[lm];B[no];W[jn];B[ko];W[fh]
;B[fg];W[so];B[sn];W[sp])
(;W[mp];B[np];W[op];B[lp];W[no];B[mo]
C[Good shape for Black. ]))
(;B[pf];W[kd];B[qg];W[ff]LB[pb:A]
C[ Black's stone at A has become a wasted move now, and having been virtually given an extra move White can attack with 4. This is good for White.]
))
(;B[pf];W[qf];B[qg];W[rg];B[qh];W[rh];B[qi];W[ri];B[qj];W[rj];B[qk];W[qb]
;B[pb];W[pa];B[rb];W[ra];B[qc];W[qa];B[sc];W[se]LB[sa:A]
C[Black will be able to make some kind of a ko, for instance by throwing in at A, but will not be able to win that ko. ]
))
(;B[pb]
C[2 vars for White's next move]
(;W[ob]
C[White wants to cover, but...];B[pf];W[qf];B[qg];W[rg];B[qh];W[rh];B[qi]
LB[qb:A]
C[It is difficult for White to win a semeai with the corner Black group, because clamping at A does not kill Black, and any other approach will give Black extra liberties. ]
;W[ri];B[qj];W[rj]
C[Black wants to cover on the 2nd line, but that is dangerous (see var)]
(;B[rk]
C[Covering at S9 is an overplay. ];W[qk]
(;B[rl];W[pj]
(;B[pk];W[ph];B[ql];W[pi];B[qk];W[mg]
C[geta])
(;B[ph];W[oh];B[og];W[pi];B[pg];W[mf]
C[ladder]))
(;B[pk];W[ql];B[rl];W[pl];B[qm];W[pj]
(;B[pi];W[oi];B[oj];W[ph];B[pj];W[nj]
C[ladder])
(;B[ph];W[oh];B[og];W[pi];B[pg];W[mf]
C[ladder])))
(;B[qk]
C[Extending is probably correct. See 2vars for White's next move]
(;W[pc];B[qc];W[rb]
C[White can kill the corner, but... ];B[qb]
(;W[ra];B[sb];W[se];B[oa];W[nb];B[sd];W[rk];B[rl]
(;W[sf];B[rc];W[sk];B[oh]TR[pb]
C[This variation also is good for Black. My conclusion is that in all of the variations starting from Q18 (marked) Black can gain an advantage. ]
)
(;W[rc];B[sf]
C[This is good for Black. ]))
(;W[pa];B[ra];W[sb];B[se];W[sc];B[rk]
C[Black easily wins this semeai.]))
(;W[qb];B[rb]
(;W[qc];B[pc]
(;W[ra];B[pa];W[rc];B[sb];W[sc];B[qa];W[sa];B[rb]
C[alive.])
(;W[pa];B[ra]
C[alive]))
(;W[pc];B[qc];W[pa];B[ra]
C[alive])
(;W[ra];B[qc];W[pa];B[qa]
C[ko]))))
(;W[qi];B[ob]
C[Crawling on the second line is the vital point in this fight. Black's corner is alive, and White does not have room to live on the upper side, so this is good for Black. ]
)))
(;W[md];B[of];W[me]
(;B[qg];W[lc]
C[This joseki is good for White. ])
(;B[lc];W[mc];B[pb]
C[Black will probably play this way to put pressure on the White group. With Black's strong position in the upper left, this fight is advantageous for Black.]
)))
(;W[de];B[df];W[cf];B[bf];W[cg];B[eg];W[bb];B[bd]LB[dj:A]
C[With the Black stone at A, this fight is bad for White. ]))
(;W[ef];B[cf];W[eh];B[dg];W[eg];B[kd]TR[dj]
C[This variation was actually played in some pro games when Kobayashi Koichi first started to play this opening. However, this is bad for White. Black forces with 4, making use of the marked stone to secure the left side in sente. White has heavy shape, and this is good for Black. ]
))
(;W[fc];B[dc];W[ic];B[kc];W[fe];B[dg];W[qo];B[pn];W[pj]
C[With the large knight kakari, White can avoid being attacked strongly. The sequence to 6 is a joseki, after which White would probably switch to the right side with 7 and 9. ]
)
(;W[fd];B[ec];W[kc];B[fc];W[oc]LB[qd:A]
C[White 3 makes miai of 4 and 5. White can be satisfied with this variation. Black A would be on a star point in the Kobayashi opening, so White 3 and 5 are slightly changed to fit Black's komoku. The comparison can be made with vars for the first move of this game. ]
))
(;B[pd];W[pp];B[cd];W[dp];B[cn];W[fq];B[dj]
C[This is the Fuseki named after Kobayashi Koichi 9P. Kobayashi playe this opening in the prime of his career with much success, to the extent that his opponents started to avoid this shape by trying different moves with 4 or 6. As this became a popular opening and was studied by all pros, it was decided that White should now play an ogeima kakari (see 4 variations for White's move). ]
(;W[ec]
C[This keima kakari was played mostly by Kato Masao 9P, who was a rival of Kobayashi, but is generally considered to be too close to the corner. ]
;B[gc];W[ee];B[df];W[hd];B[dc];W[eb];B[hc];W[id];B[gd];W[ge];B[ic];W[jd]
;B[kc];W[fe];B[eg]
C[Black gets profit on both sides, and White's group is not yet settled. This is good for Black. ]
)
(;W[ed];B[hd];W[ef];B[cf];W[eh];B[dg];W[eg];B[kd]LB[ed:A][dj:B][cn:C]
C[At first the high kakari (A) was a common move. Kobayashi had this variation ready, in which Black plays both sides and White has a weak group. The vulgar looking peep at 6 is actually quite effective, making use of the stones at B and C to secure the left side with sente. This is good for Black.  ]
)
(;W[fc]TR[dj]
C[With this move White avoids a fight in the vicinity of Black's marked stone. ]
;B[dc];W[ic];B[kc]
C[White avoids a fight in Black's sphere of influence, and Black gets profit on both sides. This is considered an even result, and is still the most popular version of this opening after a few decades of being played. ]
)
(;W[fd]
C[More recently, this high kakari has become fairly popular in professional play. ]
;B[ec]
C[Covering is not good (see var). ]
(;W[jd];B[fc];W[nc];B[qf];W[qn]LB[ce:A][cl:B]
C[White plays lightly, and still can invade the left side with A or B. Modern Go has been influenced strongly by Go Seigen's opening theory, which encourages moves such as White 1 in this variation. ]
)
(;W[fc];B[ed];W[fe];B[jc];W[ee];B[cf]
C[White is heavy. ]))))

