White made a mistake. Black to punish and win game. No komi (this was a handicap game).
This is my first problem, so it's possible I've missed something. Any comments would be appreciated.
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[9]KM[0.50]
PW[White]PB[Black]AW[ea][ga][ha][db][fb][gb][dc][fc][hc][ad][ed][ae][be][ee][fe][ie][af][bf][cf][df][ef][if][bg][eg][fg][ig][fh][hh][fi][gi]AB[ca][da][bb][cb][hb][ib][ac][cc][gc][bd][cd][dd][fd][gd][hd][id][ce][de][ge][he][ff][gf][ag][cg][dg][gg][hg][ah][bh][dh][eh][gh][ai][ci][ei]CR[ga]
(;B[ic]CR[ic]
;W[ia]CR[ia]
(;B[ec]CR[ec]
;W[eb]CR[eb]C[RIGHT
Black makes seki. H1 and J2 are miai.])
(;B[ih]CR[ih]
;W[ii]CR[ii]
;B[ec]CR[ec]
;W[eb]CR[eb]C[RIGHT
black makes seki])
(;B[hi]CR[hi]
;W[ii]CR[ii]
;B[ec]CR[ec]
;W[eb]CR[eb]C[RIGHT
black makes seki]))
(;B[ec]CR[ec]
;W[eb]CR[eb]
(;B[hi]CR[hi]
;W[ii]CR[ii]
;B[ic]CR[ic]
;W[ia]CR[ia]C[RIGHT
Black makes seki])
(;B[ih]CR[ih]
;W[ii]CR[ii]
;B[ic]CR[ic]
;W[ia]CR[ia]C[RIGHT
Black gets seki])
(;B[ic]CR[ic]
;W[ia]CR[ia]C[RIGHT
Black makes seki. H1 and J2 are miai.]))
(;B[ih]CR[ih]
;W[ii]CR[ii]
(;B[ic]CR[ic]
;W[ia]CR[ia]
;B[ec]CR[ec]
;W[eb]CR[eb]C[RIGHT
black makes seki])
(;B[ec]CR[ec]
;W[eb]CR[eb]
;B[ic]CR[ic]
;W[ia]CR[ia]C[RIGHT
black makes seki]))
(;B[hi]CR[hi]
;W[ii]CR[ii]
(;B[ec]CR[ec]
;W[eb]CR[eb]
;B[ic]CR[ic]
;W[ia]CR[ia]C[RIGHT
Black gets seki])
(;B[ic]CR[ic]
;W[ia]CR[ia]
;B[ec]CR[ec]
;W[eb]CR[eb]C[RIGHT
black gets seki])))