(;GM[1]FF[4]SZ[19]
GN[Reference]
PC[http://senseis.xmp.net/?GokyoShumyoSection4Problem5/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection4Problem5/Solution

Reference]
PL[W]

AB[db][eb][bc][cc][ce][de]
AW[bb][cb][dc][fc][gc][dd]
LB[cd:a]

;W[ec]C[W1]MN[1]
;B[ab]C[B2]MN[2]
;W[fb]C[W3]MN[3]
;B[ba]C[B4]MN[4]

;LB[cd:a]
)
