(;GM[1]FF[4]SZ[19]
GN[Mistake at 3]
PC[http://senseis.xmp.net/?GokyoShumyoSection1Problem20b/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection1Problem20b/Solution

Mistake at 3]
PL[W]

AB[aq][bq][cq][dq][eq][er][bs]
AW[co][bp][dp][ep][fq][hq][br][cr][fr]
LB[cs:a]

;W[ar]C[W3]MN[3]
;B[ds]C[B4]MN[4]
;W[fs]C[W5]MN[5]
;B[es]C[B6]MN[6]

;LB[cs:a]
)
