Another set of 4x4 problems, made on a rainy, rainy day....
Please find the best result for White!
(japanese rules)
(;SZ[4]AW[ba]AW[cc]AB[cb]AB[dc]AB[ad]AB[bd]AB[dd]C[White to play - what's the best he can do?]GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]RU[Japanese]KM[0.00]PW[Weiß]PB[Schwarz]PL[W]
(;W[bb];B[bc]
(;W[db]
(;B[cd];W[ca];B[da];W[ac];B[ab];W[db]C[...and White wins. RIGHT])
(;B[da];W[ca];B[cd];W[db]C[...and White wins.]))
(;W[ca];B[db]
(;W[ab];B[cd]C[Seki, Black wins by one point (the prisoner).])
(;W[da];B[cd];W[ab]C[Seki, Black wins by one point (the prisoner).])))
(;W[bc];B[bb]
(;W[ac];B[ab];W[cd];B[db]C[Black wins!])
(;W[ab];B[cd]C[Black wins!])
(;W[db];B[da];W[ac];B[ab];W[cd];B[bd];W[db];B[dc]
(;W[ca];B[aa]
(;W[ca];B[db]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[ba]C[Seki! Each side has 5 prisoners, so this is only a jigo!];B[db]C[Seki, each side has 5 prisoners. This is only a jigo!]))
(;W[aa];B[ca]
(;W[ba]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[aa]C[Seki, each side has 5 prisoners. This is only a jigo!]))))
(;W[db]
(;B[bb]C[This is better than B D1!]
(;W[bc];B[da];W[ac];B[ab];W[cd];B[bd];W[db];B[dc]
(;W[ca];B[aa]
(;W[ca];B[db]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[ba];B[db]C[Seki, each side has 5 prisoners. This is only a jigo!]))
(;W[aa];B[ca]
(;W[ba]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[aa]C[Seki, each side has 5 prisoners. This is only a jigo!])))
(;W[cd];B[bc]
(;W[dc];B[ca]C[Black wins])
(;W[ca];B[dc]C[Black wins])))
(;B[da]
(;W[bc];B[bb];W[ac];B[ab];W[cd];B[bd];W[db];B[dc]
(;W[ca];B[aa]
(;W[ca];B[db]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[ba]C[Seki! Each side has 5 prisoners, so this is only a jigo!]))
(;W[aa];B[ca]
(;W[ba]C[Seki, each side has 5 prisoners. This is only a jigo!])
(;W[aa]C[Seki, each side has 5 prisoners. This is only a jigo!])))
(;W[bb];B[bc];W[ca];B[cd];W[db]C[White wins, but both W C1 and B D1 were mistakes!]))))