(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2] RU[Japanese]SZ[19]KM[0.00]TM[] PW[White]PB[Black]AW[na][qa][nb][ob][qb][nc][qc][nd][qd][rd][sd][oe][of][rf][og][rg][oh][qh][sh][qi]AB[oa][pa][pb][rb][oc][pc][sc][od][pd][pe][qe][re][se][qf][sf][qg]C[how can white win this?]PL[W] (;W[ra]CR[ra] (;B[sb]CR[sb] (;W[pg]CR[pg]C[RIGHT]) (;W[pf]CR[pf]C[RIGHT]) (;W[sg]CR[sg]C[RIGHT])) (;B[sa]CR[sa] (;W[sb]CR[sb]C[RIGHT CHOICE black can play ko like this]) (;W[pg]CR[pg] ;B[rc]CR[rc]) (;W[pf]CR[pf] ;B[rc]CR[rc]) (;W[sg]CR[sg] ;B[rc]CR[rc]))) (;W[rc]CR[rc] ;B[ra]CR[ra]) (;W[sb]CR[sb] ;B[sa]CR[sa] (;W[pg]CR[pg] ;B[ra]CR[ra]) (;W[pf]CR[pf] ;B[ra]CR[ra]) (;W[sg]CR[sg] ;B[ra]CR[ra])) (;W[sa]CR[sa] ;B[ra]CR[ra]) (;W[pg]CR[pg] ;B[ra]CR[ra] (;W[pf]CR[pf] ;B[rc]CR[rc]) (;W[sg]CR[sg] ;B[rc]CR[rc])) (;W[pf]CR[pf] ;B[ra]CR[ra] (;W[pg]CR[pg] ;B[rc]CR[rc]) (;W[sg]CR[sg] ;B[rc]CR[rc])) (;W[sg]CR[sg] ;B[ra]CR[ra] (;W[pf]CR[pf] ;B[rc]CR[rc]) (;W[pg]CR[pg] ;B[rc]CR[rc])) (;W[ph]CR[ph] ;B[ra]CR[ra]))