(;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]))))