(;GM[1]FF[4]SZ[19]AP[SmartGo:3.0.1]
GN[AlphaGo_selfplay_10b]
PW[AlphaGo]
PB[AlphaGo]
KM[7.5]
RE[W+Resign]
RU[Chinese]ST[2]MU[1]
C[AlphaGo-AlphaGo Game 10 (Part 2)
Commentary by Michael Redmond 9P
Edited by Chris Garlock and Myron Souris.

This file contains the complete game commentary, with Part 2 commentary beginning at move 113. At this point, the game looked ready for a peaceful endgame, with White in the lead. By move 121, however, White has given away about 20 points, an unexpected trade that transforms the game radically. Back in a wildly dangerous middle game, complications that arise from a fight in the center will put ten groups in danger. 



]
;B[pd]
C[This game is like two games in one, and it starts with an unusual pincer by black and then a new move by white. Then there's a series of fights that goes in a circle around the board, each one contained but each quite exciting. ]
;W[dd];B[pq];W[dp];B[fq];W[cn];B[jp];W[po]
(;B[ql]
C[Black's low 2 space pincer is unusual, and the 'human' move would be a high pincer. With Black stones on both sides, White cannot play aggressively here (see var). ]
(;W[om]
C[White 10 is a new move that makes miai of the right and lower sides (see var). ]
(;B[pj];W[np]TR[om]
C[With the extra marked stone, now White can play the keima at 12 (see var). ]
(;B[nq];W[mp];B[mq];W[lp]
(;B[fc]
C[Playing away to take the initiative on the upper side shows how AlphaGo is flexible and likes to control the flow of the game. ]
;W[df];B[mc];W[ec];B[fd];W[lq]
C[White 22 is a large move that changes the status of the lower side, the LR corner, and ultimately the right side too, if Black plays away (see var). ]
(;B[qp]
C[Black 23 makes more than 10 points in the corner, and strengthens Black's position on the right side, so it is a big move with good aji. ]
;W[hc]
C[When White pincers at 24, it might seem natural to move out with the two Black stones (see var). ]
(;B[ch]
C[Showing an unhuman lack of concern for the two stones on the upper side, Alphago just plays away. Black 25 is actually a large point that takes away White's potential on the left side. ]
;W[ld]
C[When the upper right area is Black's biggest potential moyo, it is usually bad to play this shoulder hit, as it allows Black to build on that moyo. White is trying to attack Black on the upper side. ]
;B[md];W[lc];B[le];W[ke];B[kf]LB[le:A]
C[A go proverb tells us to hane at the top of two stones, as Black did with A. Black's double hane at 31 is the natural continuation, so this shape is good to remember. ]
;W[je];B[jf];W[lf];B[me];W[if];B[lg];W[ie];B[cc]TR[ch]
C[Black invades at 39, offering to sacrifice 2 stones on the right. This can work very well with the marked stone if White cooperates (see var). ]
(;W[cd]TR[fc:fd]
C[With 40, White refuses to allow Black to sacrifice the marked stones. ]
;B[jc]
C[Black 41 hits a vital point in White's shape. 41 threatens to connect to the right, but Black is also looking to play forcing moves from the left. ]
;W[lb];B[eb];W[dc]
C[Black has some forcing moves from the left (see var). ]
(;B[gf]
C[Black escapes into the center, and Black can play the tsuke next (see var). ]
(;W[ic];B[hd]TR[id]
C[With 47 Black threatens to push through at the marked point. ];W[jb];B[eh]
C[Black 49 is not a connected shape. With White, I would be tempted to continue the attack (see var). ]
(;W[qd]
C[White abandons the attack on the left, and switches to the right side. While I was tempted to attack on the left, the right side is also an important area, as another move by Black would make it a large territory. ]
;B[qc];W[qe];B[rc];W[qi]
C[White plays the widest possible extension to create enough room to make life. ]
;B[qj];W[pi];B[oi];W[oh];B[qg]
C[Black 59 hit a vital point in White's shape, threatening to connect underneath (see var). ]
(;W[rj]
C[The immediate meaning of White 60 is to stop Black from connecting on the right side. Depending on how Black continues, White can live in the upper right, or start a fight on the side (see 2  vars). ]
(;B[ni]
C[Black 61 is a solid move that closes White into the side. Allowing White to live, Black's plan is to build thickness and control the center. ]
;W[qk]
C[When White wedges at 62, the natural move seems to be for Black to cover on the 4th line (see var). ]
(;B[rk];W[pk];B[oj];W[ri];B[rm];W[pg];B[pe];W[qf];B[rg];W[rf];B[se];W[sg]
;B[sf];W[sh]
C[Black cannot kill the White group at this time (see var). ]
(;B[ol]
C[Black makes a strong wall with 77, preparing to attack White in the lower right later. This extra stone also makes a difference in the status of White's group on the right side. ]
;W[sk];B[rl]
C[In a previous comment I said that Black cannot kill the White group, but actually there is a potential ko (see var). ]
(;W[pf]
C[White protects with 80, and after this Black has no forcing moves in the area. This makes a difference later, so it is worthwhile to check out the possibilities (see var). ]
(;B[cl];W[fg];B[gg]
C[After jumping out once at 82, White stops attacking here (see var). ]
(;W[dr]
C[White 84 is an important move that protects White's LL corner. White's only unsettled group is in the lower right now. After some complicated fighting on the upper and right sides, the game seems to be simplifying a bit now. ]
;B[fh];W[db]
C[White 86 is a large move that secures the corner and gives White a lead in territory. ]
;B[kn]
C[Black 87 starts an attack on the White group in the lower right. ];W[pm]
;B[pl];W[qo];B[ro];W[rp];B[rq];W[lm];B[ln];W[pp];B[qq]LB[sp:A][rn:B]
C[With 97 it was better to take at A. Not only did Black lose a couple of points with 97, but this move left the possibility for White to play at B and cut off the Black group on the side. ]
;W[jo];B[ko];W[mn];B[mm]
C[When Black cuts at 101, White cannot capture this stone (see var).]
(;W[kp]LB[mm:A]
C[With 102, White threatens to capture Black A next (see var). ]
(;B[km];W[jq];B[ip];W[rn];B[sp];W[iq];B[hp];W[hq];B[gp];W[hh]
C[White has cleverly dealt with its weak groups, and now it seems that the endgame is about to start. White has an advantage in territory. ]
;B[dn]
C[When Black attaches at 113, I suggest that White should simply pull back (see var). ]
(;W[do];B[bn]LB[do:A]
C[I found White A it to be a very suprising move for White, as it invites the tsuke at 115. Now White will have bad shape if it protects the corner (see var). ]
(;W[dm]LB[do:A][bn:B]
C[When White has played at A and allowed Black B, White 116 becomes the only good shape move. The drawback is that White will now suffer a huge loss in territory.]
;B[bo];W[en];B[cq];W[dq];B[cr]
C[Throughout this game White had a lead in territory, but in the last few moves, White has given away about 20 points. This unexpected trade has transformed the game radically. ]
;W[dk];B[dl];W[el];B[ek];W[fl];B[ej];W[bm]
C[White 128 is a sharp move. If Black cuts, there will be a ko (see var). ]
(;B[bl]
C[Now Black has more territory than White. ];W[in]
C[White is behind in territory, and has no choice but to attack in the center. ]
;B[hn];W[im];B[hm];W[il];B[hl];W[ik];B[gk];W[ll];B[kl];W[lk];B[kk]TR[fc][qc][pg][oj][hl:il][kl:ll][en][lp]
C[About 30 moves ago, this game looked ready for a peaceful endgame to start, but now we are back in a wildly dangerous middle game. In the complications that arise from this fight in the center, all 10 of the marked groups will be put in danger, if one includes the variations I studied. Only two of these groups died in the actual game sequence.]
(;W[ji]TR[lk]
C[Instead of running out with the marked group, White adds a stone on the left, connecting that group for now. Does Black attack or defend? (see var)]
(;B[nl]
C[Black 143 is the strongest move, and White's three stones are under attack (see var). ]
TR[lk:lm]
(;W[mf]
C[With 144 White seems to be attempting to trick Black. Black avoids the obvious trap, but finds an unexpected way to go wrong (two vars). ]
(;B[fo]
C[With 145 Black missed an opportunity to win the game by capturing 3 stones in the center. ]
TR[lk:lm];W[cm];B[am];W[lj]TR[lk:lm]
C[White extends at 148, saving the marked stones. There is still some potential fighting in the center (see var). ]
(;B[fn]TR[kp]
C[White can live in the lower left now, but that will weaken the marked White group and thus change the meaning of the fight in the center (see var). ]
(;W[mi]TR[kk:ko][ln]LB[fr:A]
C[In the game, White added a move to the center with 150, finishing off the marked Black group for now and threatening Black's group on the right. While I think White could have played at A, White 150 also seems to give White a winning position. ]
;B[gr]
C[Black kills the White group in the LL corner. ];W[sn]TR[lf:mf]
C[White kills the Black group on the right side. Black can now capture the marked stones, but that will not be good enough (see var). ]
(;B[nn];W[mo];B[nm];W[qn];B[jj];W[ij];B[nh]TR[kp:mp]
C[With 159, Black still has some potential to live on the right or create a semeai with the marked White group. ]
;W[nf];B[li]
C[With 161 Black is threatening to make eyes (see var). ]
(;W[mj];B[ng]
C[Black 163 threatens to live by squeezing White in the center (see var). ]
(;W[lh]LB[of:A][ki:B]
C[This sequence in the center is forced. White 164 is the only way for White to handle the double threat of Black A or B. ]
;B[ki];W[kh];B[kj];W[mh];B[mg];W[oe];B[og];W[of];B[jh]TR[ki:ko][li][jj][ln]
C[With 173, we finally see the marked group coming back to life. This does not save the Black group on the right, but it will create a semeai with White's group on the lower side. ]
;W[kg];B[ii];W[jg];B[lr];W[kr];B[mr];W[hi];B[hj]TR[jh][ii:in][ki:ko][li][jj][ln][jo]
C[The two marked groups are a seki. White has an advantage in the semeai between Black's group on the right and White's group on the lower side. ]
;W[hr];B[hs]
C[Black 183 is an important move that prevents White from making a big eye on the side. ]
;W[on];B[op];W[oo];B[oq];W[no];B[is];W[js]
C[W190 extends White's liberties by one move. ];B[ir];W[ih];B[ji];W[nk];B[ok]
;W[ph]
C[White 196 erases the possibility of a ko, and now it is certain that White will win the semeai by one move. The game is very close now, and the immediate question is: how should Black live in the upper right corner (see var)?  ]
(;B[ob]LB[nb:A]
C[My analysis of Black playing 197 at A ends in a half point win for White, and so does the game sequence. ]
;W[fe]
C[White's tsuke at 198 threatens to cut Black off, and works in combination with the endgame play on the left side (see var). ]
(;B[ge]
C[Black 199 is the correct move. ];W[cg]TR[gh]
C[White 200 threatens to cut at the marked point (see var). ]
(;B[dg]TR[fc:fd][ge:gg]
C[Black 201 is the only way to save Black's left side territory and the marked group simultaneously. ]
;W[bg];B[bh];W[eg];B[dh];W[ee];B[gh];W[ah]LB[gc:A][ag:B]
C[Playing at A would also be a big move, but the difference between White 208 and a Black play at B is bigger. ]
;B[io];W[jn];B[gs];W[sl];B[sm];W[sj];B[jr];W[qk];B[lo];W[ml];B[ks];W[nj]
;B[kq];W[nb]LB[so:A][kr:B][bp:C]
C[If Black plays at A, the semeai will depend on the ko at B, so why does White play away with 222? One reason is that the UR corner is bigger if White can capture it, so Black must respond to 222. Also, White has some ko threats starting with C, and has an advantage in the ko fight. ]
;B[oc];W[bi];B[cj];W[qm];B[id]LB[gc:A][eb:B]
C[Black 227 forestalls a White play at A, that would cut off the stone at B and make territory for White on the side. ]
;W[pb]TR[mc:me][le]
C[White 228 is an amazingly sharp move that could have easily been missed in a human game. The immediate threat is to capture the marked stones, and the correct result is that Black's corner territory shrinks dramatically (2 vars added). ]
(;B[mb];W[ma];B[nc];W[oa]TR[bp]
C[White has a number of valid ko threats starting with a play at the marked point. These ko threats will allow White to squeeze Black's group and force it to a life with two eyes. ]
;B[na];W[bp];B[cp];W[nb];B[pa];W[qa];B[na];W[co];B[bq];W[nb];B[so];W[pk]
;B[na];W[ak];B[bj];W[nb];B[ra];W[na];B[pc];W[jd];B[fb];W[aj];B[al];W[la]
;B[qb];W[pa];B[sb];W[da];B[bk];W[ai];B[ha];W[kr]LB[gi:A][sd:B]
C[Apart from the ko at 264, A and B are the final two big points, both making a difference of 4 points. White can use the ko to play both (see var). ]
(;B[ag];W[af]LB[gi:A][sd:B]
C[If we assume that Black wins the ko and White gets the 2 big points at A and B, White will win by a 0.25 stone margin. There is no way for Black to do better than that. 

End of commentary.]
)
(;B[cf];W[bf];B[kq];W[ap];B[aq];W[kr];B[ag];W[af];B[kq];W[an];B[ao];W[kr]
;B[ce];W[be];B[kq];W[gi]LB[rd:A][ci:B]
C[How long can Black continue this ko fight? If Black plays the yose at A and uses the ko threat at B, White will win the ko and win by 0.25 stones, so Black B is not a valid ko threat. ]
;B[ci];W[ag]LB[bd:A]
C[Black is running out of ko threats. The ko threat at A loses a point. ]
;B[kr];W[fi];B[ei];W[fj];B[fk];W[sd];B[rd];W[re];B[ff];W[ef];B[ed];W[de]
;B[ja];W[ib];B[ia];W[ka];B[gb];W[hb];B[ga];W[se];B[sc];W[ea]
C[In this final endgame sequence of 40 moves, the ko fight adds complications, but all the possible trades seem to end in the same result. However Black plays, there is no escape from a 0.25 stone win for White. ]
))
(;B[pa];W[nc];B[nd];W[od]LB[pc:A][na:B]
C[White can take at A or capture 5 stones with B. White wins. ])
(;B[oa];W[nc]TR[mc:me][le]
C[Whatever Black does, the marked stones will be captured now (2 vars for Black's move). ]
(;B[nd];W[od];B[pc];W[mb]
C[White wins. ])
(;B[mb];W[pc];B[od];W[nd];B[na];W[ne];B[qb];W[ma];B[pa];W[jd]
C[White wins. ])))
(;B[bh];W[gh]TR[fg]
C[Black has no way to capture the marked stone, and Black's stones on the upper side are cut off. White wins. ]
))
(;B[ee];W[cg]LB[ee:A][fe:B][cg:C]
C[If Black plays at A and tries to capture the White stone at B, White will play the kosumitsuke at C. Black has no way to protect the left side territory and the connection  in the center simultaneously. ]
;B[dg];W[eg];B[dh];W[ef]LB[ge:A][gh:B]
C[White creates a double threat of cutting at A or B, and this is a collapse for Black. ]
))
(;B[nb];W[oc]LB[nb:A][oc:B]
C[At first  I thought a Black play at A was correct, after which White will attack at B. Black can now answer from above or below, but my studies of the endgame sequences ended with a win for White in both cases (2 vars for White's move). ]
(;B[od];W[ob];B[nc];W[na];B[pb];W[ma];B[pc];W[oa];B[ra];W[rd];B[sc];W[fe]
;B[ge];W[cg];B[dg];W[eg];B[dh];W[ee];B[gh];W[bg];B[bh];W[ah];B[gs];W[sl]
;B[sm];W[sj];B[jr];W[nj];B[ks];W[ml];B[kq];W[pk];B[fb];W[bi];B[cj];W[ak]
;B[al];W[da];B[kr];W[gb];B[ff];W[ef];B[aj];W[bj];B[bk];W[ai];B[ci];W[ag]
;B[gc];W[ga];B[id];W[jd];B[fa];W[hb];B[ed];W[cf];B[io];W[jn];B[so];W[qm]
;B[sd];W[pa];B[qa];W[mb];B[nd];W[gi];B[fi];W[gj];B[hk];W[fj];B[fk];W[ak]
;B[gd];W[aj]
C[W+0.25 stones (0.5 points in Japanese rules)])
(;B[ob];W[pc];B[pb];W[fe];B[ge];W[cg];B[dg];W[bg];B[bh];W[eg];B[dh];W[ee]
;B[gh];W[ah];B[gs];W[sl];B[sm];W[sj];B[jr];W[ml];B[ks];W[nj];B[kq];W[pk]
;B[id];W[jd];B[fb];W[bi];B[cj];W[ak];B[bj];W[aj];B[al];W[da];B[io];W[jn]
;B[kr];W[sd];B[rd];W[re];B[nc];W[od];B[rb];W[gb];B[gc];W[ga];B[ff];W[ef]
;B[ci];W[ai];B[bk];W[ag];B[fa];W[hb];B[ed];W[cf];B[gi];W[hk];B[gj];W[ma]
;B[so];W[qm];B[sc];W[se];B[na];W[mb]
C[W+0.25 stones  (1.5 points with Japanese rules)])))
(;W[of];B[ki];W[kj];B[jk];W[mh];B[mg];W[jl];B[jh];W[ii];B[lh];W[jn];B[ig]
C[White wins the semeai in the center, but Black can win by making life for the group on the right side. ]
))
(;W[lh];B[mj];W[ki];B[mk]
C[Black lives. ]))
(;B[mh];W[li];B[nf];W[nh]
C[Black can capture 2 stones with this sequence, but White has a solid lead after killing Black on the right. ]
))
(;W[fr];B[gr];W[fs];B[gq];W[ds];B[kj];W[li];B[ki];W[lh];B[kh];W[mg];B[kg]
;W[mh];B[nn];W[mo];B[ii]
C[The center is a ko or a seki. It is dangerous for White to try to kill Black on the right side (2 vars for White's move). ]
(;W[ih];B[ij];W[jj];B[jh];W[jk];B[gi];W[nm];B[qn];W[oc];B[pb];W[ob];B[pc]
;W[mb];B[rd];W[io];B[hk];W[ig]
C[White allows the Black group on the right to live, and makes a seki in the center. White gets a lot of profit from attacking Black in the UR corner, and this variation looks like a win for White. ]
)
(;W[sn];B[qm];W[qn];B[nm];W[no];B[on];W[pn];B[mr];W[lr];B[hr];W[js];B[ir]
;W[jr];B[ls];W[kr];B[op];W[oo];B[oq];W[nk];B[ok];W[nj];B[so];W[sl];B[sm]
;W[sj];B[is];W[ml];B[ms];W[nh];B[lo];W[mi];B[ks]LB[sn:A]
C[When White tries to kill Black with A, Black has an advantage in the semeai. ]
)))
(;B[kj];W[li];B[ki];W[lh];B[kh];W[mg];B[kg];W[mh];B[ii]LB[kj:A][ii:B]
C[When Black pushes through at A, Black can still get a seki in the center with the attachment at B. ]
;W[ih];B[ij];W[jj];B[jh];W[jk];B[gi];W[sn];B[gr]LB[sn:A][gr:B]
C[When White kills Black on the right side with A, Black B threatens a semeai with the White group. ]
;W[lr];B[fn];W[oc];B[pb];W[ob];B[pc];W[io];B[ig];W[hg];B[hf]LB[lr:A][fn:B]
C[White A wins the fight on the right, and Black B kills White on the left. White will win if the center becomes a seki, so Black must play the ko as shown. ]
;W[jg];B[js];W[hr];B[hs];W[nm];B[ig];W[an];B[ao];W[jg];B[qn];W[qm];B[ig]
;W[hk];B[hj];W[jg];B[so];W[pn];B[ig];W[ck];B[bk];W[jg];B[sm];W[qn];B[ig]
;W[gj];B[fj];W[jg]LB[gl:A]
C[The ko goes on, but I will stop here. I can say that I lean towards a win for White. After White wins the ko in the center, the aji of a cut at A will cause trouble for Black in the lower left area. ]
))
(;B[li];W[nf];B[mb]LB[nf:A][mb:B]
C[I suggest that this as the winning sequence that Black should have played. Black captures the 3 cutting stones, after which A and B are miai. (2 vars for White's move)]
(;W[fk];B[fj];W[gj];B[io];W[jn];B[gl];W[kj];B[lj]LB[gl:A]
C[When White cuts off the lower side Black group, Black A makes miai of living on the side and attacking White in the center (2 vars for White's move). ]
(;W[gn];B[hj];W[gi];B[ij];W[jj];B[jk];W[lo];B[hk]LB[lo:A][mk:B][ml:C]
C[Black captures White's group in the center. It might seem that White has created a seki with A, but Black can later capture 3 stones with B and C, so the seki is false. ]
)
(;W[hk];B[fm];W[em];B[fn];W[go];B[fo];W[gn];B[er]LB[hk:A][go:B]
C[If White adds a stone from the outside with A, and continues to attempt to kill Black with B, Black can win the semeai to capture White's group in the corner. ]
))
(;W[nm];B[ml];W[cm];B[am];W[fe];B[ge];W[cg];B[dg];W[bg];B[bh];W[eg];B[dh]
;W[ee];B[gh];W[ah];B[hi];W[ii];B[hj];W[ij];B[kg];W[ig];B[fb];W[bi];B[cj]
LB[fe:A][ah:B][fb:C]
C[When we look at the endgame sequence, White A is a tesuji that makes the most of Black's weak connection. I will make a detailed explanation of this move when it occurrs in the game sequence. B and C are miai. Black is winning by about 10 points before komi. ]
))
(;B[nf];W[lj]LB[nf:A][lj:B]
C[Black A falls into the trap when White extends at B (2 vars for Black's move). ]
(;B[ng];W[li];B[sj];W[pc]LB[ng:A][pc:B]
C[When Black plays at A and then tries to kill the White group on the side, it runs into trouble when White cuts at B (2 vars). ]
(;B[oc];W[pb]
(;B[ob];W[rd];B[sd];W[re];B[sc];W[qb]
C[White wins the semeai. ])
(;B[qb];W[rd];B[sd];W[ob];B[nb];W[od];B[oe];W[nc]
(;B[mb];W[sb];B[sc];W[qa];B[ra];W[pa]
C[White wins the semeai. ])
(;B[nd];W[na];B[oc];W[ma]
C[White connects on the side to kill Black in the corner. ])))
(;B[pb];W[oc];B[od];W[nd];B[oe];W[sd];B[rd];W[re];B[se];W[ob];B[pa];W[mb]
;B[ra];W[nh];B[mh];W[mi];B[nc];W[sn]LB[pb:A][mi:B]
C[When Black plays atari underneath with A, Black can live in the corner, but is in trouble when White cuts at B. White wins the semeai to kill Black's group on the right side. ]
))
(;B[kj];W[li];B[ki];W[lh];B[kh];W[mg];B[kg];W[mh]LB[ih:A][sn:B]
C[White can play at A to kill Black in the center, or B to kill Black on the side. White wins. ]
)))
(;W[lj];B[kj];W[nm];B[ml];W[li];B[ki];W[lh];B[kh];W[mg];B[mf];W[mh];B[nn]
LB[lj:A][nn:B]
C[When White escapes with A, Black pushes through to connect in the center, and White can connect to the right side. Black's group on the the right side is in danger now, thus Black's cut at B ( 2 vars for White's move). ]
(;W[ih];B[hj];W[ij];B[hi];W[ii];B[mo];W[fr];B[gh]LB[mo:A]
C[In this variation, the added value for Black is the capture at A, which connects Black's groups and will make a difference to the endgame plays in the UR corner. Black wins.]
)
(;W[mo];B[qm];W[pn];B[ig];W[hg];B[ih]LB[mo:A][qm:B]
C[If White connects at A, Black can force with B to save the right side group with sente. Black can then cut White off in the center to win the game. ]
)))
(;B[lj];W[hk];B[gl];W[nl];B[nk];W[ml];B[jj];W[ii];B[gi];W[hi]LB[lj:A]
C[When Black plays the hane at A, all of the weak groups will connect up, and the endgame will start. ]
;B[cm];W[fr];B[kg];W[ki];B[kj];W[ig];B[bg]
C[This looks like a close game. ]))
(;W[lj];B[kj];W[li];B[ii];W[ji];B[jj];W[ij];B[hi];W[ki];B[io];W[jn];B[ih]
LB[lj:A][gh:B]
C[When White extends at A, this diagram shows what I believe to be Black's safest way to achieve a win. The center becomes a seki. Added value for Black is that the cut at B has dissappeared, and that will make a big difference in how the endgame moves on the left are played. ]
;W[nl];B[nk];W[ml];B[cm];W[fr];B[bf];W[be];B[cf]
C[Black wins. ]))
(;B[cm];W[bp];B[cp];W[co]
C[Black has two choices, but White will get a ko either way (see var).]
(;B[bl];W[ao];B[am];W[br];B[bq];W[aq]
C[White can get a ko in the corner. ])
(;B[bq];W[an];B[ap];W[ck];B[bl];W[al]
C[This ko inside Black's territory is good for White. ])))
(;W[bo];B[cm];W[co];B[en]LB[do:A][en:B]
C[After playing at A, it is painful for White to protect the corner territory. If we assume that Black will get territory in the center, it can be said that White has lost about 5 points by exchanging A for B. ]
))
(;W[co];B[ih];W[hg];B[ij];W[dm];B[dl];W[em];B[gm];W[dg]LB[dg:A][dh:B][ff:C]
C[White has a lead in territory, and the outcome will depend on how much  Black can make in the center. When White plays at A, next White can push through at B, or play C to capture some Black stones on the upper side, so this is troublesome for Black. ]
))
(;B[jq];W[ml];B[nm];W[km];B[jn];W[nl];B[nn];W[mo]
C[White captures the Black cutting stones.]))
(;W[ml];B[nm];W[nl];B[nn];W[mo];B[on];W[pn];B[ll];W[km];B[mk]
C[Black wins the race to capture. ]))
(;W[fh];B[db];W[cb];B[eg];W[ef];B[ff];W[fi];B[hh];W[ei];B[cg];W[cj];B[bj]
LB[bb:A]
C[When White pushes through at 1, Black crawls once at 2 and cuts White with 4 and 6, and the White group in the corner is not completely alive. Later Black can attack with a play at A, and this is not good for White. ]
))
(;B[ng];W[ck];B[sj];W[og];B[qh];W[rd];B[sd];W[pc]LB[ng:A][sj:B][pc:C]
C[When White plays away after Black A, and Black tries to kill the White group with B, Black will have trouble when White cuts at C (two vars). ]
(;B[oc];W[pb]TR[sd:sf]
C[When Black takes from above, Black will have trouble saving the marked stones (2 vars). ]
(;B[ob];W[re];B[sc];W[qb]
C[Black loses the semeai in the corner. ])
(;B[qb];W[ob];B[nb];W[od];B[oe];W[nc];B[nd];W[na];B[oc];W[ma]
C[White connects on the side, and the Black group in the corner dies. ]))
(;B[pb];W[oc];B[oe];W[ob];B[qa];W[oa]
C[Black's corner group dies.])))
(;W[ck]
C[White 1 is a big point that sets up to attack Black in the upper left, so if we assume that the group on the right is alive, White definitely wants to play here (2 vars for Black's move). ]
(;B[pf];W[qh];B[og];W[rh];B[qg]LB[qg:A]
C[Throwing in at A is a tesuji that can be found in tsumego problems. Does White take or connect? (two vars)]
(;W[rg];B[nh];W[of];B[ph];W[pc];B[pb];W[oh]LB[oc:A][ob:B][ph:C]
C[When we assume that White A forces Black B, then Black must fight the ko at C to kill the White group. ]
;B[db];W[ng];B[bc]
C[This shows one possible trade. The damage to Black's group in the UR corner is not as bad as one might have expected, and Black's gain in the UL corner is big. This is good for Black. ]
)
(;W[ph];B[sj];W[pc];B[oc];W[pb];B[ob];W[of]LB[ph:A][og:B]
C[When White has connected at A, the value of capturing Black's stone at B is reduced, as White does not get an eye by capturing that stone. ]
;B[nf];W[ng];B[oe];W[mh];B[li];W[rd];B[sd];W[qb];B[rb]LB[qg:A][re:B]
C[Black's stone at A makes a difference in the corner when White tries to make an eye here. White cannot play the atari at B, and the Black stones on the side escape. White is dead. ]
))
(;B[sj];W[pc];B[oc];W[pb];B[ob];W[pf]LB[sj:A][rd:B][qh:C]
C[If Black simply takes away one eye with A, White can live with this sequence. Next White can capture 2 Black stones with B to make a second eye, or if Black protects, White has two eyes by playing at C. ]
)))
(;B[pf];W[qh];B[og];W[rh];B[sj];W[of];B[ng];W[pc]
C[Black can reduce White to one eye with 1~5, but this leaves a weakness in Black's shape when White cuts at 6 and 8. ]
;B[pb];W[oc];B[oe];W[ob];B[qa];W[sd];B[rd];W[re];B[se];W[oa]
C[In the end, Black's corner group dies. ]))
(;B[pk];W[rk];B[pm];W[ol];B[pl];W[pg];B[rg]LB[ri:A][sf:B]
C[When White plays at  6, Black 7 is the shape move, and Black threatens A or B next. ]
;W[rh];B[sf];W[qh];B[sh];W[si];B[sg];W[qf];B[sd];W[of]LB[of:A]
C[Black can reduce White to one eye on the side, but after White A, White can make an eye in the center. ]
;B[ng];W[od];B[pc];W[pe];B[oc];W[rl];B[rm];W[nh];B[mh];W[nf]LB[pf:A][sj:B]
C[White finally lives, with one eye at A and the other at B. ]))
(;B[rk];W[pg];B[ri];W[rh];B[sj];W[rg]LB[rk:A][rg:B]
C[If Black covers at A, White can live with the sequence to B. ])
(;B[pg];W[qk];B[pk];W[rk];B[pm];W[rh];B[rg]TR[ph]
C[Black 1 is a strong move that stops White from living in the upper right, and with the marked cut, White can't escape into the center either. White has no choice but to try to live on the side with 2~6. ]
;W[ol];B[pl];W[rm];B[rl];W[qo];B[nj];W[sl];B[rn];W[ro]TR[oj]LB[qm:A][sn:B]
C[Threatening the marked cut, White can eventually for Black to protect, and make a ko on the side. If Black plays A, White can make a ko with B.  Black's LR corner is becoming weak now, so this looks good for White. ]
))
(;W[pg];B[ri]
C[Black connects, and White has no eyes. ]))
(;W[fg];B[gg];W[fh];B[eg];W[ef];B[ff];W[fi];B[hh];W[dj]LB[db:A]
C[White White attacks at 1, Black must escape to the center with 2~8. Locally, White has an advantage after 9. Black was hoping to use the aji at A, but the side group is too weak for that to work. ]
))
(;W[eh];B[hd];W[ic];B[id];W[jb];B[jd];W[kd];B[gb]LB[eh:A][cb:B]
C[If White splits Black on the left with A, Black can take away White's eyespace with this sequence. Next Black can live with a play at B. This is good for Black. ]
))
(;B[hd];W[ic];B[id];W[jb];B[jd];W[kd];B[gb];W[ge];B[gd];W[eg]
C[Locally, Black wants to play the sequence from 1 to 7, taking away White's eye space, but this is premature. White surrounds Black with 10, and Black is cramped on the side. ]
))
(;W[eb];B[ce];W[de];B[bf]TR[fc:fd]
C[Black scoops out the corner, sacrificing the marked stones. With the added value of creating a living group on the left side, this is good for Black]
))
(;B[ge];W[ld];B[lc];W[jd]
C[If Black moves out with 1, White will also run out with 2 and 4. This will be a running fight in the center, and looks about even to me. ]
))
(;B[ch];W[qq];B[qr];W[rr];B[qp];W[rq];B[pp];W[qo];B[rp];W[ro]LB[rr:A]
C[White's hane at A is the tesuji to attack Black's corner. When White covers at 10, Black might seem to have a number of choices (3 vars for Black's move.) ]
(;B[so];W[sn];B[sp];W[pr];B[or];W[qs];B[rn]LB[qk:A]
C[Black can connect to the side, but the is some troublesome aji with a White attachment at A. This is feasible for White. ]
)
(;B[pr];W[sp];B[lr];W[kr];B[ls];W[jq];B[op];W[oo]LB[pr:A]
C[When Black connects at A, Black will be able to live, but takes a lot of damage on the side. This is good for White. ]
)
(;B[sr];W[pr];B[sq];W[qs];B[or];W[op];B[oq];W[so];B[sp];W[mr];B[os];W[nr]
LB[sr:A]
C[Black's attachment at A is a well-known tesuji that kills the White corner, but it does not work well when Black has a shortage of liberties. Black has no way of avoiding a ko in the corner, and this is good for White. ]
)))
(;B[lq];W[kp];B[kq];W[jo];B[ip];W[nc]
C[If Black connects on the side, White will force from above and take sente to play the kakari at 6. This looks about even, and is how I would play with Black. ]
))
(;B[oo];W[op];B[pp];W[qo];B[on];W[oq];B[rp];W[qp];B[qq];W[ro]
C[It is difficult for Black to save the corner and fight on the outside simultaneously (two vars for Black's move). ]
(;B[rq];W[pm];B[mn];W[pr]
C[White captures the corner. ])
(;B[or];W[nr];B[pr];W[rq];B[rr];W[sp];B[sr];W[nn];B[pn];W[pm]
C[White captures the cutting stones.])))
(;B[np];W[pk];B[qk];W[pj];B[qj];W[pi];B[qh];W[og]
C[When Black answers on the lower side with 1, White can press Black into a low position on the right side. This is good for White. ]
))
(;W[np];B[oo];W[op];B[pp]
C[If White immediately presses at 1, Black will cut with 2 and 4 (2 vars). ]
(;W[on];B[qo];W[no];B[qn]LB[np:A]
C[Although White can capture in a ladder, White ends with an eyeless shape and Black has all the territory. The wasted stone at A reduces the efficiency of White's ponnuki. ]
)
(;W[qo];B[on];W[rp];B[nr];W[pm];B[mo]LB[rp:A][pm:B]
C[White A is the tesuji that allows White to jump out at B. Black captures two stones to have a good position on the lower side, and this favors Black. ]
)))
(;B[pl]
C[In this fuseki, the high pincer is Black's most common move. Jumping  is considered to be bad for White, and switching to the right side is most popular in recent games (see 2 vars). ]
(;W[no];B[nq];W[lo];B[mp];W[mo];B[pi]
C[This is the textbook pattern in which Black can surround both the lower and right sides. White still has an unsettled group, and this is good for Black. ]
)
(;W[qj];B[rl];W[qf];B[qh];W[rh]LB[qj:A][rl:B]
C[When White plays at A, Black B is the strongest fighting move with which Black attempts to put pressure on White's side group. There is no set pattern that I know of after this, but I can say the fighting will start on the right side. ]
)))

