(;GM[1]FF[4]SZ[19]
GN[Ko fight = half a solution]
PC[http://senseis.xmp.net/?BeginnerExercise44/Solution]AP[GoWiki:2009]
DT[2016-05-29]
C[Diagram from http://senseis.xmp.net/?BeginnerExercise44/Solution

Ko fight = half a solution]
PL[B]

AB[be][bg][cg][ch][di][dj][ck][dk][cm][bn][co]
AW[bh][bi][cj][ak][bk][bl][am][bm]
CR[ai]

;B[bj]C[B1]MN[1]
;W[aj]C[W2]MN[2]
;B[ci]C[B3]MN[3]
;W[ah]C[W4]MN[4]

;CR[ai]
)
