(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AB[fh][fg][gf][hf][ef][dg]AW[gg][gh][hg][ff][fe][fd][hd]C[page 2
problem 1

Black to play and rescue two stones.]GN[2 problem 1]SO[bgj 201])(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AW[hi][hg][gg][fg][eh][dh]AB[ci][ch][cg][dg][eg][ff][gf][hf][if][ee]C[page 4
problem 2

Black to play and kill.]GN[4 problem 2])(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[13]CA[UTF-8]AB[ml][lk][lj][kj][jj][ij][hj][gj][ik][fk][ej][el][dl]AW[fl][fm][gk][hk][il][jk][kk][ll][lm]C[page 7
problem 3

Black to play and kill.]GN[7 problem 3]SO[bgj 201])(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[19]CA[UTF-8]AB[dd][pp][dp][pd]DT[1975-03-29]PW[Magari Reiki ]PB[Paul Prescott]GN[8 split shape game]WR[9p]WT[Nihon Ki-in]BR[3d]BT[UK]RE[W+9]C[page 8
go jottings 22 - part 1
problem 1

example of split shape];B[pd];W[qf];B[nd];W[ql];B[qn];W[fc];B[jc];W[df];B[ef];W[eg];B[ee];W[cc];B[dc];W[cd];B[cb];W[de];B[fd];W[dg];B[je];W[id];B[jd];W[hf];B[hd];W[cn];B[fp];W[jq];B[lq];W[fr];B[fq];W[gr];B[er];W[dr];B[eq];W[cq];B[es];W[cp];B[jo];W[kp];B[lp];W[ko];B[jn];W[kn];B[jm];W[hp];B[ho];W[mo];B[oq];W[go];B[hq];W[ip];B[hr];W[gp];B[gq];W[en];B[hm];W[iq];B[fo];W[fn];B[kr];W[qc];B[qd];W[rd];B[pc];W[rb];B[qb];W[rc];B[km];W[mm];B[jj];W[bb];B[db];W[fk];B[qj];W[pk];B[pj];W[nk];B[pg];W[pf];B[og];W[of];B[mg];W[mf];B[me];W[nf];B[mi];W[ng];B[oi];W[rn];B[ro];W[pn];B[qo];W[np];B[nq];W[qm];B[fi];W[gh];B[gi];W[ei];B[hh];W[fh];B[gk];W[gl];B[hk];W[fj];B[hi];W[ff];B[fe];W[pb];B[ob];W[qa];B[mk];W[ml];B[lk];W[nj];B[qg];W[sm];B[rf];W[re];B[rg];W[mh];B[ni];W[qe];B[lg];W[lf];B[kg];W[kf];B[jf];W[nb];B[oc];W[mc];B[md];W[oa];B[lb];W[lc];B[mb];W[kb];B[nc];W[ma];B[na];W[jg];B[pa];W[kh];B[qb];W[he];B[hc];W[gd];B[gc];W[ge];B[ed];W[fb];B[eb];W[ba];B[gb];W[pb];B[hg];W[oa];B[nb];W[gf];B[li];W[lh];B[dq];W[cr];B[do];W[co];B[qk];W[ok];B[rl];W[rm];B[rk];W[so];B[rp];W[jr];B[eo];W[ie];B[ic];W[sp];B[sq];W[sn];B[rq];W[oo];B[dn];W[dm];B[po];W[om];B[gm];W[fl];B[fm];W[em];B[gg];W[fg];B[io];W[ji];B[ki];W[hl];B[il];W[fa];B[ga];W[ca];B[ea];W[ii];B[ij];W[hn];B[im];W[gn];B[ln];W[lo];B[lm];W[mp];B[mq];W[mn];B[ds];W[cs]C[White won by 9 points.])(;ST[2]GM[1]SZ[19]FF[4]AP[Sabaki:0.52.2]CA[UTF-8]FG[259:]GN[13 go jottings problem 1]AB[rd][dj][cd][hc][ej][ed][pe][oc][cl][kq][nq][qd]PM[2]AW[pn][cn][qe][qf][pp][cf][di][ei][og][qj][dp][fj]SO[bgj 201]C[page 13
go jottings 22 - part 1
problem 1

White has just played at 1 - hane at the head of the two Black stones
How should Black respond?
]LB[fj:1](;B[fk]C[diagram 1a];W[cj];B[ck];TR[dj][ej]W[ci])(;B[ci]C[diagram 1b];W[ch];B[bi];W[fi];B[el]L[cj][bj]))(;ST[2]GM[1]SZ[19]FF[4]AP[Sabaki:0.52.2]CA[UTF-8]FG[259:]GN[14 go jottings problem 2]PW[ ]AB[gp][bn][dq][dn][ck][fq][bo][dr][do][cm][ep]PB[ ]PM[2]AW[em][cq][en][cr][co][eo][el][bp][cp][dp]SO[bgj 201]C[page 14
go jottings 22 - part 1
problem 2

White's corner group is the L-shaped group, so it is dead. White needs to find a way out.

White to play
](;W[cn]C[diagram 2a];B[dm];W[bl];B[bm];W[cl];B[dl];W[dk])(;W[bl]C[diagram 2b];B[cl];W[cn];B[dm];W[bm]))(;ST[2]AP[Sabaki:0.52.2]CA[UTF-8]FF[4]GM[1]SZ[19]PM[2]AW[hc][dd][jc][fq][cf][qm][rp][qj][cp][dp][eb]GN[14 go jottings problem 3 ]FG[259:]AB[cn][ck][qe][ch][fe][pc][pp][he][ef][nq][fc]SO[bgj 201]C[page 14
go jottings 22 - part 1
problem 3

Black to play A or B?
E17 or F18]LB[ec:A][fb:B](;B[ec]C[diagram 3a];W[dc];B[fb];W[mc];B[db];W[cb];B[ea])(;B[fb]C[diagram 3b];W[mc];B[cc];W[dc];B[cb];W[db];B[be]L[lc]))(;ST[2]AP[Sabaki:0.52.2]CA[UTF-8]FF[4]GM[1]SZ[19]PM[2]AW[nh][ne][lf][lc][mc][nf][kg][md][og][lh][le][kb]GN[14 go jottings problem 4]FG[259:]AB[me][kc][mf][nc][oc][kd][mg][ld][nd]C[page 14
go jottings 22 - part 1
problem 4

Can black save the three marked stones?
Black to play]TR[me][mf][mg](;B[jb]C[diagram 4a];W[nb];B[ob];W[mh])(;B[mb]C[diagram 4b];W[lb];B[jb];W[nb];B[ob];W[ma];B[ka];W[mh])(;B[la]C[diagram 4c](;W[lb];B[jb];W[ka];B[mb];W[ma];B[nb])(;W[nb]C[diagram 4d](;B[lb];W[mb];B[jb];W[mh])(;B[ma]C[diagram 4e];W[mb];B[ob];W[lb];B[jb]))))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[13]CA[UTF-8]AB[kl][kk][jj][ij][hj][hk][gk][fl][el]AW[dl][dk][ek][fk][gj][gi][hh][ji][ki][kj][jk][jl][ll]C[page 19
problem 4

Black to play and live.]GN[19 problem 4]SO[bgj 201])(;GM[1]FF[4]SZ[19]AP[Sabaki:0.52.2]CA[UTF-8]GN[24 tsumego advice problem 1]DT[2020-11-24]RU[Simple]AB[bp][cp][cq]AW[bo][co][do][dp][dq]AE[bb][bc][bd][eb][ec][lb][lc][ld][nb][ob][rb][rc][rd][cc][hc][md][nd][od][pd][qd][sd][he][qe][op][qp][eq][nq][nr][ns][pq][pr][sq][ar][fr][gr][hr][qr][rr][cs][es][rs]PL[B]C[page 24
advice for doing tsumego part eight

problem 1 from part seven

Black to play]SO[bgj 201](;B[cr];W[dr])(;B[dr];W[er](;B[cr];W[ds];B[cs];W[ap];B[aq];W[br];B[fr];W[eq];B[es];W[gq])(;B[br];W[ds];B[cs]))(;B[br](;W[dr];B[aq])(;W[aq];B[dr];W[er];B[ds](;W[ap];B[ar])(;W[ar];B[ap];W[bs];B[cr]))))(;GM[1]FF[4]SZ[19]AP[Sabaki:0.52.2]CA[UTF-8]GN[26 tsumego advice problem 2]DT[2020-11-24]RU[Simple]AB[cp][dp][ep][fp][fq][hq]AW[cq][dq][eq]AE[da][db][dc][dd][de][df][dg][dh][qa][qb][bb][cb][sb][ec][pc][pd][pe][rc][be][bf][bh][ch][cl][el][rl][rm][rn][bo][co][qo][qp][qq][so][sq][br][cr][dr][rs]PL[B]C[page 26
advice for doing tsumego part eight

problem 2 from part seven

Black to play](;B[bp](;W[bq];B[er];W[dr];B[fr])(;W[br]))(;B[er];W[dr];B[fr];W[br];B[bp];W[cs])(;B[bq];W[br];B[bp];W[fr](;B[ar];W[bs];B[dr];W[ds];B[es];W[cr])(;B[gr];W[fs])))(;GM[1]FF[4]SZ[19]AP[Sabaki:0.52.2]CA[UTF-8]GN[27 tsumego advice problem 3]DT[2020-11-24]RU[Simple]AB[bp][cp][dp][ep][fp][bq][fq][hq][gr]AW[cq][dq][eq][ar][br][fr]AE[da][db][dc][dd][de][df][dg][dh][qa][qb][bb][cb][sb][ec][pc][pd][pe][rc][be][bf][bh][ch][cl][el][rl][rm][rn][bo][co][qo][qp][qq][so][sq][cr][dr][rs]PL[B]C[page 27
advice for doing tsumego part eight

problem 3

Black to play](;B[er];W[dr];B[fs];W[ds])(;B[ds];W[er];B[es];W[gs];B[hs];W[fs];B[cr]))(;GM[1]FF[4]SZ[19]AP[Sabaki:0.52.2]CA[UTF-8]GN[27 tsumego advice problem 4]DT[2020-11-24]KM[-7.5]RU[Simple]AB[bp][cp][dp][ep][fp][fq][hq]AW[cq][dq][eq][br]AE[da][db][dc][dd][de][df][dg][dh][qa][qb][bb][cb][sb][ec][pc][pd][pe][rc][be][bf][bh][ch][cl][el][rl][rm][rn][bo][co][qo][qp][qq][so][sq][cr][dr][rs]PL[B]C[page 27
advice for doing tsumego part eight

problem 4

Black to play]SO[bgj 201](;B[bq];W[fr])(;B[er];W[dr](;B[fs];W[cs];B[bq];W[ar];B[ds])(;B[fr]))(;B[fr](;W[er];B[bq];W[ar])(;W[dr];B[cs])(;W[cs];B[bq];W[ar])))(;GM[1]FF[4]SZ[19]AP[Sabaki:0.52.2]CA[UTF-8]GN[28 tsumego advice problem 5]DT[2020-11-24]RU[Simple]AB[bp:fp][bq][fq:fr][hq]AW[cq:eq][ar:br][er]AE[da:dh][qa:qb][bb:cb][sb][ec][pc:pe][rc][be:bf][bh:ch][cl][el][rl:rn][bo:co][qo:qq][so][sq][cr:dr][rs]PL[B]C[page 28
advice for doing tsumego part eight

problem 5

Black to play]SO[bgj 201];B[ds];W[es];B[cr])(;SZ[19]FF[4]ST[2]GM[1]CA[UTF-8]AP[Sabaki:0.52.2]OT[45 secs Fisher]KM[7.5]EV[British Championship 2022]TM[6000.0]RO[1]DT[2022-08-20]PB[Bruno Poltronieri]PM[2]FG[259:]PW[Gaoge Wang]RE[W+2.5]PC[The KGS Go Server at http://www.gokgs.com/]GN[30 game commentary]C[page 30
game review by Artem Kachanovskyi ]RU[BGA]SO[bgj 201]AN[Artem Kachanovskyi];B[pd];W[dp];B[dd];W[qp];B[oq];W[po];B[qf];W[cf];B[lq];W[cc];B[cd];W[dc];B[ed];W[bd];B[be];W[bc];B[cn];W[ce];B[fq];W[dn];B[dm];W[en];B[cp](;C[This move opts for an old-fashioned joseki that was considered bad for White even in the pre-AI era. AI agrees with that estimation and preferms modern alternatives from the diagrams.]W[co];B[bo];W[do];B[bm];W[cq];B[bp];W[em];B[dl](;LB[hp:A]C[White 32 is played in a wrong direction. The two black stones on the lower side are solid, so Black can play a shoulder-hit at A to separate White's group on the left from the stone on the lower side. This happened a little later in the game.]W[iq];B[cg];W[bf];B[ql];W[pq];B[op];W[oo];B[no];W[nn];B[mo];W[om];B[hp];W[ip](;B[hn]C[This shape is vulnurable - a few moves later White used its weakness to link up their stones on the lower side.];C[White had to play at 48 immediately, using the weakness of the Black's shape as it was still there.]W[jn](;B[hl];C[Excellent move, perhaps Black didn't see it coming.]W[gp](;B[go];W[gq];PM[2]FG[259:];B[fp];W[gr];B[fn];W[er];B[cr];W[dr];B[bq];W[dq];B[fr];W[fs](;B[bs]C[A passive move - see the diagram for explanation.];W[kp];B[jr];W[kq];B[kr];W[lp];B[mq];W[mp];B[np];LB[jn:A]C[The fight on the lower side was successful for White. Black hasn't made many points, while White entered the center of the board from two directions - 70 and A, making the black group in the middle vulnurable.]W[el](;B[pi];C[A great move, launching a sente attack on the group on the lower side.]W[or];B[nr];W[pr];B[mn];W[mm];B[lm];W[ml];B[kn];W[jm];B[ir];W[hr];B[ll];W[jk];B[hj];W[lk];B[ls]C[The fact that Black was forced to play here means that White's attack was successful - White created influence on the outside, while Black occupied a neutral point.];W[hg];B[fj];W[ek];B[ej];W[dk];B[eg](;C[This move is active, but doesn't work well.]W[gk];B[il];W[gj];B[gi];W[hi];B[fk];W[gh];PM[2]FG[259:];B[fi];W[hk];B[ik];W[ij];B[gl];W[hj];B[jl]C[This move cuts off the big white group in the lower left while also protecting the black group, bringing Black back into the game.];W[ci];B[ch];W[di];B[eh];W[bi](;B[bh]C[Unfortunately for Black, this move was a big mistake.];W[fl];B[gf](;W[fh];B[ei];W[ef];B[fg];W[hf];B[gd];W[he];B[ff];W[ge];B[fe];W[hd];B[gc];W[hb];B[hc];W[ic];B[gb];W[ib];B[ck];W[dj];B[df];W[de];B[ee];W[dh];B[ec];TR[bh]C[A painfull loss for Black: the three stones on the left, including the triangled move Black played earlier, are now cut off and White linked up their group with the corner. Moreover, Black still has to spend a move on the upper side to live there, and White can extend on the upper side, making use of the wall they made while attacking Black.]W[dg];B[db];W[kk];B[kl](;C[A wrong way of using the thickness in the center.]W[pb];B[oc];W[ob];B[mc];W[qc];B[jd];W[kc];PM[2]FG[259:];B[kd];W[lc];B[ld];W[mb];B[nb];W[na];B[nc];W[lb];B[mk];W[ki];B[lh];W[li];B[mh];W[rm];B[rd];W[qd];B[re];W[rl];B[qk];W[rc];B[nk];C[ ]W[ol];B[bj];W[ai];B[ih];W[hh];B[jg];W[id];B[qm];W[rn];B[rk];W[pe];B[oe];W[qe];B[pf];W[mi];B[ni];W[cb];B[da];W[ok];B[oj];W[kh];B[kg];W[cl];B[cm];W[bk];B[bl];W[ak];B[qn];W[qo];PM[2]FG[259:];B[pn];W[on];B[nl];W[nm];B[jc];W[jb];B[sl];W[sd];B[sm];W[ro];B[sf];W[ga];B[fa];W[ha];B[fb];W[pk];B[pj];W[mj];B[nj];W[jh];B[ig];W[je];B[ke];W[sn];B[sk];W[jf];B[kf];W[pc];B[od];W[fm];B[gm];W[lo];B[ln];W[ca];B[if];W[ie];B[ii];W[ji];B[im];W[io];B[ho];W[hq];B[jq];W[jp];B[al];W[aj];B[os];W[ps];B[ns];W[pp];B[is];W[es];B[se];W[sc];B[ef];W[cj];B[cl];W[ah];B[hs];W[gs];B[in];W[jo];B[eo];W[ep];B[fo];W[ds];B[cs];W[eq];B[km];W[ko];B[gg];W[pm];B[pl];W[tt];B[tt];W[tt])(;MN[1]PM[2]FG[259:];W[nc];B[nd];W[md];B[ne];W[pc];B[qc];W[oc];B[qd];W[me];B[nf];C[White should enclose the territory on the upper side and in the center. This way White is at least ten points ahead.]W[lg]))(;MN[1]PM[2]FG[259:];C[ ]W[kl];B[km];W[kk];LB[jo:B][gm:A]B[im]C[It might seem like White 1 cuts off the black group, but Black 4 saves the situation: A and B are miai.]))(;MN[1]PM[2]FG[259:];B[gf];W[ie];B[gd];W[ic];B[fl];W[bh];B[nc]C[In this diagram it's not Black, but White who has to play a passive move at 6 on the left side. Black, in turn, is in time to play a big move in the upper-right corner. The game is playable for both sides. Compare this result with the actual game.]))(;MN[1]PM[2]FG[259:];W[ii];B[kl];W[jl];B[kk];W[kj];B[lj];LB[mk:A][nc:B]C[White 1 links up the white stones in the center and seals in the black group. White is not aftraid of Black wedging at 2 and 4: after White 7, Black A is a big move, but not urgent. Instead of 2 and 4, Black would be forced to protect their group in the left part of the board, so White would be in time to play a big move at B afterwards.]W[ki]))(;PM[2]FG[259:];LB[qr:A]B[or]C[Even though this move looks passive, it prevents White from playing here and threatens to jump at A weakening the corner. This move would be called "honte" in the Japanese therminology - a "fair" move, slow-looking but good.]))(;MN[1]PM[2]FG[259:];B[jr]C[ ];W[jq];LB[km:A][br:B][ar:C]B[kr]C[Instead of Black 61 in the game, this sequence expands Black's life base on the lower side and reduces White' one. Next White would be forced to move towards the center, for example at A. White B would only make one eye to their group after Black C, so their is no need to prevent this move.]))(;MN[1]PM[2]FG[259:];B[hq]C[It's tempting to resist here, but White would anyway link up their stones in the end.];W[ho];B[go];W[io];B[fp];W[gn];B[fo];W[gm];B[hr];W[hm]))(;MN[1]PM[2]FG[259:];B[hq]C[Black had a chance to fix their shape.];W[kp];B[kq]))(;MN[1]PM[2]FG[259:];B[ho]C[Black 1, a solid extension, is a more reliable shape than Black 45 in the game.];W[io];B[hn];W[in];B[hm]))(;MN[1]PM[2]FG[259:];W[nc];B[hp];C[This diagram demonstrates a more natural development of situation instead of White 32 in the game. Black 2 on the lower side can be ignored - White can occupy another big point, for example 3 on the right. There is no way for Black to start a direct and profitable attack.]W[qk]))(;MN[1]PM[2]FG[259:];W[cq];B[co];LB[gp:A][ck:B]C[After White 3, the follow-up depends on the board position. In this case, Black can play A and White would respond at B, but that's just one of the possible variants.]W[dq])(;MN[1]PM[2]FG[259:];W[cm];B[co];W[dl];LB[em:A]B[dq]C[Here is another modern joseki: White exchages the corner for the outside influence. Note that White can play it only if the ladder, which Black can start by playing A instead of 4, works for White. In this case, Black's hoshi in the upper-right corner breaks the ladder, so White would be forced to choose the sequence from the previous diagram.]))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AB[fh][fg][gf][hf][ef][dg]AW[gg][gh][hg][ff][fe][fd][hd]C[page 41
problem 1 solution

Black to play and rescue two stones.]GN[42 problem 1 solution]SO[bgj 201](;B[hh]C[Filling a liberty gives White eye shape.];W[hi](;B[ig];W[ih];B[if];W[he];B[fi];W[gi])(;B[ih];W[ig];B[if];W[ii];B[fi];W[ie];B[gi];W[he]))(;B[ig];W[ih];B[gi];W[if];B[ie];W[ig](;B[he];W[id]C[White escapes])(;B[ii];W[hi]C[White lives.]))(;B[ih]C[This is the correct play.](;W[ig](;B[if];W[gi];B[fi]C[White has fewer liberties.])(;B[gi]C[This is the best liberty for Black to fill as it leaves fewer ko threats.]))(;W[he];B[ig];W[ge];B[if]C[Also no good for White.]))(;B[hi]C[This 2-1 point fails.];W[if];B[ie];W[ig];B[he];W[id]))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AW[hi][hg][gg][fg][eh][dh]AB[ci][ch][cg][dg][eg][ff][gf][hf][if][ee]C[page 41
problem 2 solution

Black to play and kill.]GN[42 problem 2 solution]SO[bgj 201](;B[di]C[Sometimes pushing is correct, but white can get eyes.];W[ih](;B[fi];W[gh])(;B[gh];W[fh];B[fi](;W[gi])(;W[ei];B[ig];W[gi])))(;B[fi]C[Jumping to here is no good either](;W[ih];B[fh];W[gh])(;W[fh]C[White can even play here.];B[ih];W[ig];B[hh];W[ei]))(;B[ih]C[This is the correct first play - the key point for both sides.](;W[ig]C[Cutting off 1 doesn't help White.];B[hh];W[gh];B[fi](;W[fh];B[di];W[ei]C[This is self-atari])(;W[gi];B[di])(;W[ei];B[di];W[fh]))(;W[fi]C[This is maybe White's strongest defence.];B[gh];W[hh];B[fh](;W[gi];B[fh];W[gh];B[di]C[However White still can only make one eye.])(;W[ig];B[ei];W[gi];B[fh]))))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[13]CA[UTF-8]AB[ml][lk][lj][kj][jj][ij][hj][gj][ik][fk][ej][el][dl]AW[fl][fm][gk][hk][il][jk][kk][ll][lm]C[page 41
problem 3 solution

Black to play and kill.]GN[42 problem 3 solution]SO[bgj 201])(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[13]CA[UTF-8]AB[kl][kk][jj][ij][hj][hk][gk][fl][el]AW[dl][dk][ek][fk][gj][gi][hh][ji][ki][kj][jk][jl][ll]C[page 43
problem 4 solution

Black to play and live.]GN[43 problem 4 solution](;B[lk]C[Black can try and make use of the corner to get ahead in the fight.];W[km];B[ml];W[lm];B[il];W[lj];B[gm];W[em];B[im];W[hl]C[However the shape to the left can only make one eye.])(;B[km]C[This is the correct play that allows Black to live.](;W[lk];B[il];W[jm];B[im];W[lm];B[gm];W[em];B[hl]C[The extra forcing move allows Black to make two eyes.])(;W[il]C[This is White's strongest reply and
Black needs to respond carefully.
There are several ways to
go wrong.](;B[hl]C[Blocking here is suicidal.];W[lk];B[gm];W[em])(;B[lk]C[Black must play here.];W[hl];B[gl];W[lj];B[mk]C[This is best. Black has four liberties
and so does White, so you might
think White can win by playing
next, but White will need to play
on one of their own liberties.];W[mj];B[ik];W[lm];B[hm]C[Black wins.]))))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AB[hh][gh][fg][ff][dg][cg]AW[eh][fh][gg][hg][fe][ge]C[page 43
problem 5 solution

Black to play and capture two white stones.]GN[44 problem 5 solution]SO[bgj 201](;B[gf]C[Black can start here.];W[hf];B[he];W[hd](;B[dh]C[This is a mistake.];W[ih];B[hi]C[This move sets up a ko shape.];W[gi];B[fi];W[ei];B[di]C[Black has to win the ko to escape death in the corner.])(;B[ih]C[This is the correct play which avoids ko.];W[ie]C[White has to take here before filling the side edge liberty of Black.];B[dh];W[ig];B[ei];W[gi];B[eg]C[Black is a liberty ahead.]))(;B[eg]C[This leads to a ko.];W[ih];B[hi];W[gi];B[fi];W[ei];B[dh];W[gi])(;B[ih]C[However best move is to play here immediately.];W[gi];B[gf];W[hf];B[he];W[hd];B[eg];W[ie];B[dh];W[ig];B[ei]C[This ends the same shape but is better style.]))(;GM[1]FF[4]AP[Sabaki:0.52.2]SZ[9]CA[UTF-8]AB[hh][gh][fg][ff][dg][cg]AW[eh][fh][gg][hg][fe][ge]C[page 41
problem 5

Black to play and capture two white stones.]GN[41 problem 5]SO[bgj 201])