(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[9]KM[6.50]
PW[Blanc]PB[Noir]AW[cc][bd][cd][dd][ce][de][ee][fe][he][ef][gf][if][cg][gg][ch][dh][eh][gh][di][gi]AB[db][dc][ed][fd][gd][hd][be][ge][bf][cf][df][ff][bg][dg][eg][fg][fh][ei][fi]LB[ha:Y][ia:N][bf:?]C[Can White kill the black group on B4? Play on Y(es) or N(o) to start.]PL[B]
(;B[ia]
;W[bh]C[Let's see how you can defend you group now.]
(;B[ah]
;W[ag]
(;B[af]
;W[bi]
(;B[cb]
;W[ad]
;B[ac]
(;W[bb]C[CHOICE]
(;B[ba]C[ White cannot do anything against the black group.RIGHT])
(;B[ab]
;W[ba]C[Seki ! a strange one, but seki anyway.RIGHT]))
(;W[ab]C[CHOICE]
;B[bb]
;W[bc]C[ White cannot do anything against the black group.RIGHT]))
(;B[ad]
;W[ac]
;B[cb]
;W[ae]C[And now, where to find your ko-threat ? :p]))
(;B[bi]
;W[ai]C[And now, where to find your ko-threat ? :p ... Next move, play at A5 to capture or connect and capture later. You lose.]))
(;B[cb]
;W[ad]
(;B[ac]
;W[bb]
(;B[ae]
;W[bc]
(;B[ba]
;W[ab]
(;B[ca]
;W[ag]C[You lose.])
(;B[ah]
;W[ag]C[You lose.]))
(;B[ah]
;W[ag]C[You lose.]))
(;B[ba]
;W[ag]C[You lose.])
(;B[ah]
;W[ag]
(;B[af]
;W[bi]
;B[ba]C[ White cannot do anything against the black group.RIGHT])
(;B[bi]CR[bi]
;W[ai]CR[ai]
;B[bc]CR[bc]
;W[ab]CR[ab]
;B[ah]CR[ah]
;W[ec]CR[ec]
;B[ci]CR[ci]C[RIGHT White could not do anything against the the middle black group.])))
(;B[ah]
;W[ag]
;B[af]
;W[ae]C[You lose.]))
(;B[ad]
;W[ae]
;B[af]
;W[ac]))
(;B[ha]C[White cannot do anything against the black group.]))