(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
SZ[13]
AW[ca][ja][ab][bb][cb][jb][mb][cc][jc][ad][bd][jd][kd][ae][ke][af][if][ag][jg][kg][ah][ii][ki][li]AB[da][db][kb][lb][bc][dc][kc][dd][ld][be][ce][de][bf][bg][bh][ai][bi]LB[cd:A]C[Make life for the 4 stones in the upper right corner! You have one ko threat at A (C10). Assume there are no further ko threats on the rest of the board!]PL[B]
(;B[ka]
;W[mc]
(;B[ma]
;W[le]
(;B[md]
;W[la]
;B[cd]
;W[ac]
;B[ma]C[Correct! :)
RIGHT])
(;B[lc]
;W[la]
;B[cd]
;W[ac]
;B[ma]C[Correct! :)
RIGHT]))
(;B[md]
;W[ma])
(;B[lc]
;W[ma]
;B[le]
;W[lf])
(;B[le]
;W[lc]))
(;B[mc]
;W[la]
(;B[ma]
;W[ka]
;B[le]
;W[mb]
;B[cd]
;W[ac]
;B[ma]
;W[lf]
;B[me]
;W[mb])
(;B[le]
;W[ka]
;B[ma]
;W[me]
;B[lf]
;W[mb]
;B[cd]
;W[ac]
;B[ma]
;W[mf]
;B[lg]
;W[mb]))
(;B[le]
;W[la]
;B[mc]
;W[ka]
;B[ma]
;W[me]
;B[lf]
;W[mb]
;B[cd]
;W[ac]
;B[ma]
;W[mf]
;B[lg]
;W[mb]))