Please find the best result for White!
(japanese rules)
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[4]KM[0.00]
PW[Weiß]PB[Schwarz]AW[ad]AB[aa][ba][ab]C[White to play - what's the best he can do?]PL[W]
(;W[cb]CR[cb]
;B[bc]CR[bc]
(;W[cc]CR[cc]
;B[cd]CR[cd]
(;W[ca]CR[ca]
(;B[bd]CR[bd]
(;W[bb]CR[bb]
;B[ac]CR[ac]
;W[dc]CR[dc]
;B[db]CR[db]
;W[da]CR[da]C[Seki & jigo (1 prisoner each) RIGHT])
(;W[dc]CR[dc]
;B[db]CR[db]
(;W[da]CR[da]
;B[ac]CR[ac]C[Seki & jigo (1 prisoner each) RIGHT])
(;W[bb]CR[bb]
;B[ac]CR[ac]
;W[da]CR[da]C[Seki & jigo (1 prisoner each) RIGHT])
(;W[dd]CR[dd]
;B[ac]CR[ac]
;W[da]CR[da]C[Jigo & seki (1 prisoner each) RIGHT])))
(;B[bb]CR[bb]
;W[bd]CR[bd]))
(;W[bd]CR[bd]
;B[ac]CR[ac]
;W[bd]CR[bd]
;B[ca]CR[ca]
;W[dd]CR[dd]
;B[db]CR[db]C[Seki, Black wins by one point (2 prisoners against 1)!])
(;W[bb]CR[bb]
;B[ca]CR[ca]
(;W[db]CR[db]
;B[ac]CR[ac]C[Black makes an eye and wins.])
(;W[bd]CR[bd]
;B[ac]CR[ac]
;W[bd]CR[bd]
;B[ad]CR[ad]
(;W[dc]CR[dc]C[Seki, Black wins by three points (the prisoners).])
(;W[db]CR[db]C[Seki, Black wins by three points (the prisoners).]))))
(;W[bb]CR[bb]
;B[cc]CR[cc]
;W[ac]CR[ac]
;B[bd]CR[bd]
;W[ac]CR[ac]
;B[ad]CR[ad]
;W[ca]CR[ca]
;B[db]CR[db]
;W[ac]CR[ac]
;B[ab]CR[ab]C[Black wins.]))
(;W[bc]CR[bc]
;B[cb]CR[cb]
;W[cc]CR[cc]
;B[dc]CR[dc]
;W[bb]CR[bb]
;B[cd]CR[cd]
(;W[ca]CR[ca]
;B[da]CR[da]C[Seki, Black wins by one point (the prisoner).])
(;W[db]CR[db]
;B[da]CR[da]C[Seki, Black wins by one point (the prisoner)]))
(;W[cc]CR[cc]
;B[cb]CR[cb]
;W[bc]CR[bc]
;B[dc]CR[dc]
;W[bb]CR[bb]
;B[cd]CR[cd]
(;W[ca]CR[ca]
;B[da]CR[da]C[Seki, Black wins by one point (the prisoner).])
(;W[db]CR[db]
;B[da]CR[da]C[Seki, Black wins by one point (the prisoner)])))