(;AP[goproblems]AW[cb]AW[eb]AW[cc]AW[dc]AB[bc]AW[bd]AW[be]AW[ce]AB[db]AB[fb]AB[ec]AB[ed]AB[dd]AB[cd]TR[cc]TR[dc]TR[cb]C[black to win the capturing-race. Get the marked Stones.](;B[bb](;W[da](;B[ba](;W[ca](;B[fa]C[];W[ac];B[ea];W[ab];B[db]C[CHOICERIGHT])(;B[ea];W[fa](;B[ga];W[ac];B[ea]C[Just ko])(;B[gb];W[ac]))(;B[ac];W[ad])(;B[ad];W[ab])(;B[ab];W[ad]))(;W[fa];B[ca]C[RIGHT]))(;B[fa];W[ba])(;B[ca];W[ba])(;B[ad];W[ba])(;B[ea];W[fa]))(;W[ca](;B[ba];W[da](;B[fa];W[ac];B[ea];W[ab];B[db]C[CHOICERIGHT])(;B[ea];W[fa](;B[ga];W[ac];B[ea]C[Just ko])(;B[gb];W[ac])))(;B[ea]C[RIGHT])(;B[da];W[ea](;B[ba]C[RIGHT])(;B[db];W[ba])(;B[da];W[ba])(;B[fa];W[ba]))(;B[fa];W[ba])))(;B[da](;W[bb];B[ea];W[ac])(;W[ca];B[ea];W[bb]))(;B[ea];W[bb];B[ca];W[ba];B[da];W[ac])(;B[fa];W[da])(;B[ca](;W[da];B[bb];W[ba];B[fa];W[ab];B[ea];W[ac])(;W[bb];B[ea];W[ba];B[da];W[ac]))(;B[ba];W[bb]))