(;GM[1]FF[4]SZ[19]
GN[Weak attack]
PC[http://senseis.xmp.net/?KyuExercise31/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?KyuExercise31/Solution

Weak attack]
PL[W]

AB[da][ea][ga][ab][cb][eb][hb][bc][ec][hc][bd][dd][ed][fd][gd]
AW[ha][ia][db][ib][cc][dc][ic][ad][cd][hd][id][ae][be][ce][de][ee][fe][ge][he]

;W[fb]C[W1]MN[1]
;B[gb]C[B2]MN[2]
;W[fc]C[W3]MN[3]
;B[ac]C[B4]MN[4]

;
)
