(;GM[1]FF[4]SZ[19]
GN[But it occurs to me that White could simply recapture at 4, creating a pretty complicated ko.]
PC[http://senseis.xmp.net/?GSATEProblem142]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?GSATEProblem142

But it occurs to me that White could simply recapture at 4, creating a pretty complicated ko.]
PL[B]

AB[nb][pb][oc][od][oe][of][pf][qf][rf][mg][ng][rg][sg]
AW[la][mb][qb][ic][mc][nc][qc][jd][nd][pd][sd][ne][pe][qe][re][kf][lf][nf][sf]

;B[qa]C[B1]MN[1]
;W[ra]C[W2]MN[2]
;B[oa]C[B3]MN[3]
;W[na]C[W4]MN[4]

;
)
