(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2] RU[Japanese]SZ[19]KM[0.00] PW[me]PB[also me]AW[da][ea][ab][hb][ib][ob][pb][qb][bc][dc][ec][fc][gc][pc][bd][hd][pd][qd][rd][be][de][qe][cf][qf][bg][cg][dh][ao][bo][oo][ro][np][pp][qp][rp][bq][cq][nq][oq][pq][rq][pr][bs][cs][rs]AB[ha][bb][cb][db][eb][fb][gb][nb][cc][mc][oc][qc][rc][cd][od][sd][ae][ce][oe][re][bf][pf][rf][pg][qg][cm][qm][bn][nn][on][rn][co][mo][po][qo][dp][mp][dq][mq][qq][dr][lr][nr][or][qr][sr][ds][ps]LB[ff:5][nf:6][ln:7][eo:8]PL[B] (;B[ac] ;W[af] ;B[aa] ;W[ca] ;B[ga]C[seki, very similar to problem 4 - infact I already found this as a possible variation for problem 4 (although obviously it is wrong as in problem four white can get a ko to kill)!]) (;B[sb] ;W[rg] ;B[rh] ;W[rb] ;B[sg] ;W[sc] ;B[rc]C[pretty simple one, interesting to see what heppens if white plays first though...]) (;W[sb] ;B[sc] ;W[rb] ;B[se] ;W[rg]C[obviously white lives this way]) (;W[rb] ;B[sb] ;W[sc] ;B[rc]C[but this doesn't work! despite seeming like the obvious move]) (;B[rr] ;W[qs] (;B[ss] ;W[qs] ;B[rs] ;W[sq] ;B[so] ;W[qs] ;B[qr] ;W[os]C[obviously this doesn't work...]) (;B[os] ;W[sq] ;B[ss] ;W[qs] ;B[rs] ;W[qs] ;B[qr]C[this is better, now white only has at best one eye])) (;B[cr]C[given following variations this push is actually wrong] ;W[br] ;B[aq] (;W[ar] ;B[bp] ;W[ap] ;B[cp]) (;W[bp] ;B[ar]) (;W[cp] (;B[an] ;W[ar]C[doesn't work...]) (;B[ar] ;W[ap] ;B[an] ;W[as]) (;B[bp] ;W[ap]))) (;B[aq] (;W[ar] ;B[bp] ;W[ap] (;B[cp] ;W[cr]) (;B[cr] ;W[br] ;B[cp])) (;W[cp] ;B[ar]C[black needs the extra liberty on the A2 stone to make the throw in at B4 work hence the push at C2 is wrong] (;W[br] ;B[ap]) (;W[cr] ;B[an] ;W[bp] ;B[br]))))