(;GM[1]FF[4]SZ[19]
GN[Ko is all W can get since black has outside liberties]
PC[http://senseis.xmp.net/?GokyoShumyoSection3Problem78/Attempts]AP[GoWiki:2009]
DT[2011-01-06]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection3Problem78/Attempts

Ko is all W can get since black has outside liberties]
PL[W]

AB[bb][db][dc][cd][dd]
AW[eb][ec][ed][be][ee][cf]

;W[bc]C[W1]MN[1]
;B[bd]C[B2]MN[2]
;W[ba]C[W3]MN[3]
;B[ca]C[B4]MN[4]
;W[ab]C[W5]MN[5]

;
)
