(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PB[Black to play]AW[cp][dp][ep][bq][eq][br][dr]AB[bn][co][do][eo][ap][bp][fp][fq][er][fr]C[This is the problem position.
Black to play.]
(;B[cq]C[Some folk say never miss the chance to play an atari...]
;W[dq]
;B[ds]C[and this is also atari]
;W[cr]
(;B[cs]C[This next is wrong.]
;W[bs]
;B[aq]
;W[ar]C[This lives easily.])
(;B[aq]C[And this is also wrong.]
;W[ar]
;B[cs]
;W[bs]C[Also easily alive.])
(;B[ar]C[This is the trickiest move.]
;W[aq]
;B[bs]
;W[as]C[This way is ko.])
(;B[bs]C[This is the correct way - white cannot survive.]
;W[cs]
;B[ar]
(;W[aq]C[This is self-atari.])
(;W[as]
;B[aq]C[No ko -just dead.])))
(;B[ds]C[Sometimes there is death in the hane...]
(;W[cs]C[... and if white tries this...]
;B[cq]C[... this black catches white short of liberties.]
(;W[dq]
;B[cr])
(;W[es]
;B[dq]))
(;W[cr]C[But white can play this stronger move]
;B[aq]
;W[ar]
;B[cs]
;W[bs]C[And white easily lives again.]))
(;B[cs]C[The placement is sometimes good.]
;W[cr]
;B[ds]
;W[bs]
;B[aq]
;W[ar]C[But again two easy eyes.])
(;B[aq]C[This move also seem to make it too easy for white.]
;W[ar]
(;B[ds]
;W[cr]
;B[cs]
;W[bs])
(;B[cq]
;W[dq]
;B[ds]
;W[cr]
;B[cs]
;W[bs])
(;B[cs]
;W[cr]
;B[ds]
;W[bs]))
(;B[ar]C[This one looks trickier]
(;W[cq]
;B[cs]
;W[ds]
;B[bs]
;W[aq]
;B[es]
;W[as]C[This is a ko, but white can resist harder])
(;W[aq]C[This is stronger for white]
(;B[cs]
;W[bs]
(;B[cq]
;W[dq]
;B[ds]
;W[cr]C[White lives])
(;B[ds]
;W[cr]C[Also Life]))
(;B[cq]
;W[dq]
(;B[ds]
;W[cr]
;B[cs]
;W[bs])
(;B[cs]
;W[bs]
;B[ds]
;W[cr]))
(;B[bs]
(;W[cs]C[white cannot defend this way...]
;B[cq]C[... as this is double atari.]
;W[cr]
;B[dq]
;W[as]C[Only some of the white stones live.])
(;W[cr]C[Does this work?]
;B[cq]
;W[dq]
;B[ds]
(;W[cs]C[This is self-atari.])
(;W[as]C[So white will have to play ko.]))
(;W[as]
;B[cq]
;W[dq]
;B[ar]
;W[cr]
;B[ds]
;W[as]C[This is still ko.])))
(;W[bs]C[This white fails]
;B[cq]
;W[dq]
;B[ds]
;W[cr]
;B[aq])
(;W[ds]C[And this fails]
;B[cq]
;W[dq]
;B[bs]
(;W[aq]C[This is self-atari.])
(;W[cr]
;B[aq]C[This is dead.])))
(;B[bs]C[Black also try this move first.]
(;W[aq]
;B[ds]C[If black connects out white is clearly dead.]
(;W[cr]
;B[cs])
(;W[cs]
;B[cr]
;W[cq]
;B[cs]))
(;W[ds]C[This stops the edge connection.]
;B[cq]
;W[dq]
;B[ar]
;W[cr]
;B[aq]C[But White dies ])
(;W[cs]
;B[cq]
;W[dq]
;B[ar]
(;W[aq]C[This is self atari])
(;W[as]C[This looks like a ko, but...]
;B[aq]C[... black connects and white is dead.]))
(;W[cr]
;B[cq]
;W[dq]
(;B[ar]
;W[aq]
;B[ds]
;W[as]C[This one is ko again.])
(;B[ds]C[But black avoid the ko by playing here.]
;W[cs]
;B[ar]
(;W[aq]C[Self-atari.])
(;W[as]
;B[aq]C[No Ko.])))
(;W[cq]
;B[ds]
;W[cs]
;B[cr]C[This is ko again.])))
