This position was fun to analyse, but I don't know if it works as a problem (where you have to play only half the moves)?!
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[7]KM[0.00]
PW[Weiß]PB[Schwarz]AW[ca][da][ea][cb][fb][gb][ec][ad][bd][dd][ed][fd][ce][de][bf][df][ff][dg][gg]AB[aa][ba][fa][eb][ac][bc][cc][dc][fc][be][ee][fe][ge][ef][eg][fg]C[Black to play and draw!]
(;B[bb]CR[bb]
(;W[ga]LB[db:A]CR[ga]C[W A is also very interesting - please take a look at it!]
;B[db]CR[db]
;W[cd]CR[cd]
(;B[fa]CR[fa]
;W[ea]CR[ea]
(;B[da]CR[da]
;W[gc]CR[gc]
(;B[gf]CR[gf]
;W[gd]CR[gd]
;B[fa]CR[fa]C[..and Black connects the ko: jigo! RIGHT])
(;B[fa]CR[fa]
;W[gd]CR[gd]
;B[gf]CR[gf]
;W[ea]CR[ea]C[White connects the ko and wins by one point. Black took the ko too early!]))
(;B[gd]CR[gd]
;W[gc]CR[gc]
;B[gf]CR[gf]
;W[fa]CR[fa]
;B[da]CR[da]
;W[fc]CR[fc]C[Jigo! RIGHT])
(;B[gf]CR[gf]
;W[da]CR[da]
;B[ca]CR[ca]
;W[gd]CR[gd]
;B[fa]CR[fa]
;W[ea]CR[ea]
;B[da]CR[da]
;W[gc]CR[gc]
;B[fa]CR[fa]C[... and Black connects the Ko: Jigo! RIGHT]))
(;B[gd]CR[gd]
;W[ab]CR[ab]C[Uh-oh :)]))
(;W[db]CR[db]
;B[eb]CR[eb]
;W[db]CR[db]
;B[da]CR[da]
;W[ea]CR[ea]
;B[cd]CR[cd]
(;W[ca]CR[ca]C[Since Black has one ko threat more than White, White can't win the ko. Ignoring the first threat is best!]
;B[af]CR[af]
;W[gd]CR[gd]
;B[gf]CR[gf]
;W[cb]CR[cb]
;B[ae]CR[ae]
;W[bg]CR[bg]C[After some hectic play, Black wins by one point!])
(;W[ae]LB[ca:A]CR[ae]C[This is two points worse than W A.]
;B[eb]CR[eb]
;W[gd]CR[gd]
;B[gf]CR[gf]
;W[ea]CR[ea]
;B[af]CR[af]
(;W[ag]CR[ag]
;B[eb]CR[eb]
;W[gc]CR[gc]
;B[ea]CR[ea]
;W[ga]CR[ga]
;B[cb]CR[cb]C[Black wins by three points!])
(;W[ca]CR[ca]
;B[be]CR[be]
;W[cb]CR[cb]
;B[bg]CR[bg]
;W[cf]CR[cf]
;B[ae]CR[ae]
;W[cg]CR[cg]
;B[ag]CR[ag]C[Black wins by three points!]))))
(;B[db]CR[db]
;W[bb]
;B[ab]CR[ab]
;W[ea]LB[ga:B][bb:C][cb:A]TR[db]CR[ea]C[Black is dead! W A also kills the group. W B in answer to the marked black stone would have been a mistake, allowing Black to reach the solution with B C.])
(;B[gf]CR[gf]
;W[db]CR[db]C[The group in the bottom right was alive already....])
(;B[gd]CR[gd]
;W[gc]CR[gc]
;B[gf]CR[gf]
;W[db]CR[db]C[B G4 was gote!]))