(;GM[1]FF[4]SZ[19]
GN[Necessary forcing move]
PC[http://senseis.xmp.net/?GokyoSeimyoVolume3Problem13/Attempts]AP[GoWiki:2009]
DT[2009-07-30]
C[Diagram from http://senseis.xmp.net/?GokyoSeimyoVolume3Problem13/Attempts

Necessary forcing move]
PL[W]

AB[jb][kb][mb][rb][sb][ic][jc][lc][mc][pc][qc][nd][od]
AW[lb][kc][rc][sc][jd][kd][ld][md][pd][qd][sd][ne][oe][re]
LB[pa:a][pb:b][qb:c]

;W[qa]C[W1]MN[1]

;LB[pa:a][pb:b][qb:c]
)
