(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[7]KM[0.00]
PW[White]PB[Black]
;AW[bb][eb][bc][cc][dc][ec][fc][cd][ed][ce][ee][df][ff]AB[ba][ea][ga][ab][cb][db][fb][ac][gc][bd][ae][ge][af][gf][bg][eg][fg]LB[da:A]C[black to kill white]
(;B[be]CR[be]
;W[dg]CR[dg]C[Now the best black can do is seki.]
(;B[cf]CR[cf]
;W[cg]LB[bf:A]CR[cg]C[A is forced]
;B[bf]CR[bf]
;W[fd]LB[gd:A]CR[fd]C[Please convice yourself A is forced.]
;B[gd]CR[gd]
;W[ef]LB[dd:B][de:A]CR[ef]C[Please convice yourself A or B is forced and play at A.]
;B[de]CR[de]
;W[gg]CR[gg]
;B[fg]CR[fg]
;W[eg]CR[eg]C[seki])
(;B[cg]CR[cg]
;W[cf]LB[bf:A]CR[cf]C[Please follow A to reach seki. Other lines of play are at best seki, too.]
;B[bf]CR[bf]
;W[fd]LB[gd:A]CR[fd]
;B[gd]CR[gd]
;W[ef]LB[de:A]CR[ef]
;B[de]CR[de]
;W[gg]LB[fg:A]CR[gg]
;B[fg]CR[fg]
;W[eg]CR[eg]C[seki]))
(;B[bf]CR[bf]
;W[dg]LB[gd:B][be:A]CR[dg]C[Now black collapses. Follow A or B to see why.]
(;B[be]CR[be]
;W[fd]LB[gd:A]CR[fd]
;B[gd]CR[gd]
;W[ef]LB[cf:A]CR[ef]
;B[cf]CR[cf]
;W[fe]LB[cg:A]CR[fe]
;B[cg]CR[cg]
;W[gg]LB[fg:A]CR[gg]
;B[fg]CR[fg]
;W[eg]LB[de:A]CR[eg]
;B[de]CR[de]
;W[gg]CR[gg]C[black has no ko threat.])
(;B[gd]CR[gd]
;W[ef]LB[gb:A]CR[ef]
;B[gb]CR[gb]
;W[fe]LB[fa:A]CR[fe]
;B[fa]CR[fa]
;W[fd]LB[da:A]CR[fd]
;B[da]CR[da]
;W[gg]LB[fg:A]CR[gg]
;B[fg]CR[fg]
;W[eg]LB[ca:A]CR[eg]
;B[ca]CR[ca]
;W[gg]LB[aa:A]CR[gg]
;B[aa]CR[aa]
;W[ad]CR[ad]C[black collapses.]))
(;B[cf]CR[cf]
;W[be]LB[ad:A]CR[be]C[A is forced.]
;B[ad]CR[ad]
;W[bf]LB[dg:A]CR[bf]C[The best black can do is A.]
;B[dg]CR[dg]
;W[cg]CR[cg]C[black has no ko threat.])
(;B[cg]CR[cg]
;W[dg]LB[be:A]CR[dg]C[Now the best black can do is seki. Please follow A.]
;B[be]CR[be]
;W[cf]LB[bf:A]CR[cf]
;B[bf]CR[bf]
;W[fd]LB[gd:A]CR[fd]
;B[gd]CR[gd]
;W[ef]LB[de:A]CR[ef]
;B[de]CR[de]
;W[gg]LB[fg:A]CR[gg]
;B[fg]CR[fg]
;W[eg]CR[eg]C[seki])
(;B[dg]CR[dg]
;W[bf]CR[bf]
(;B[be]CR[be]
;W[cf]CR[cf]
;B[cg]CR[cg]
;W[fd]CR[fd]
;B[gd]CR[gd]C[RIGHT White is dead.])
(;B[cg]CR[cg]
;W[be]CR[be]
;B[ad]CR[ad]
;W[fd]CR[fd]
;B[gd]CR[gd]C[RIGHT White is dead.]))
(;B[ef]CR[ef]
;W[dg]LB[fe:A]CR[dg]C[A is forced. If white got to play A black loese.]
;B[fe]CR[fe]
;W[be]LB[ad:A]CR[be]C[A is forced.]
;B[ad]CR[ad]
;W[bf]CR[bf]C[Black has two eyes but its right groups can't connect to the eyes.])
(;B[fe]CR[fe]
;W[dg]LB[ef:A]CR[dg]C[A is forced. If white got to play A black loses.]
;B[ef]CR[ef]
;W[be]LB[ad:A]CR[be]C[A is forced.]
;B[ad]CR[ad]
;W[bf]CR[bf]C[Black get two eyes but its right groups can't connect to the eyes.])
(;B[de]CR[de]
;W[dg]CR[dg]C[Now the best black can do is seki. Use the navirgator to see how to reach seki in other variations.])
(;B[dd]CR[dd]
;W[dg]CR[dg]C[Now the best black can do is seki. Use navirgator to see how to reach seki in other variations.])
(;B[da]CR[da]C[White has one true eye and black has several false eyes. But if black can connect its false eyes in a loop, then black can kill white.])
(;B[gd]CR[gd]
;W[dg]CR[dg]C[Now the best black can do is seki. Use the navigator to see how to reach seki in other variations.]))