(;GM[1]FF[4]SZ[19]
GN[Main line]
PC[http://senseis.xmp.net/?GokyoShumyoSection1Problem18/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GokyoShumyoSection1Problem18/Solution

Main line]
PL[B]

AB[bp][bq][cq][eq][er]
AW[cn][fn][bo][ap][cp][dp][fp][fq][fr]
LB[fs:a]

;B[bs]C[B1]MN[1]
;W[es]C[W2]MN[2]
;B[ds]C[B3]MN[3]
;W[dr]C[W4]MN[4]
;B[dq]C[B5]MN[5]
;W[cs]C[W6]MN[6]
;B[cr]C[B7]MN[7]

;LB[fs:a]
)
