(;GM[1]FF[4]SZ[19]
GN[Big gain]
PC[https://senseis.xmp.net/?XuanxuanQijingProblem308/Solution]AP[GoWiki:2009]
DT[2023-02-10]
C[Diagram from https://senseis.xmp.net/?XuanxuanQijingProblem308/Solution

Big gain]
PL[B]

AB[jb][jc][kc][lc][pc][qc][rc][md][nd][od]
AW[kb][lb][pb][mc][nc][oc][pd][qd][rd]

;B[ob]C[B1]MN[1]
;W[oa]C[W2]MN[2]
;B[pa]C[B3]MN[3]
;W[qb]C[W4]MN[4]
;B[na]C[B5]MN[5]
;W[rb]C[W6]MN[6]
;B[mb]C[B7]MN[7]

;
)
