(;GM[1]FF[4]SZ[19]
GN[Black to play and make [oiotoshi\]. The solution is a ko for life.]
PC[http://senseis.xmp.net/?GokyoShumyoSection5Problem7]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection5Problem7

Black to play and make [oiotoshi\]. The solution is a ko for life.]
PL[B]

AB[bb][db][gb][dc][ec][fc][gc][ad][bd][cd][de]
AW[da][ga][ab][cb][eb][fb][hb][bc][hc][hd][be][fe][cf][df][ef]


;
)
