(;GM[1]FF[4]SZ[19]
GN[Mistake (ii) at 3]
PC[http://senseis.xmp.net/?GokyoShumyoSection1Problem21/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection1Problem21/Solution

Mistake (ii) at 3]
PL[W]

AB[nb][ob][mc][md][qd][rd][oe][qf]
AW[pb][sb][nc][oc][qc]
LB[pa:a][ra:b]

;W[oa]C[W1]MN[1]
;B[mb]C[B2]MN[2]
;W[rb]C[W3]MN[3]
;B[qa]C[B4]MN[4]

;LB[pa:a][ra:b]
)
