(;AW[ad]AW[bc]AW[cb]AW[da]AW[db]AW[dc]AW[dd]AW[cd]AB[ab]AB[bd]AB[be]AB[bf]AB[ce]AB[de]AB[ed]AB[ec]AB[eb]AB[ea]C[Black to kill.]AP[goproblems]
(;B[bb];W[ba]LB[ef:Tenuki]
(;B[ae];W[ac];B[cc];W[bc]
(;B[ac]C[Your stones are connected, and white does not have space for eyes.RIGHT])
(;B[ad]C[Your stones are connected, and white does not have space for eyes.RIGHT])
(;B[aa];W[ac]))
(;B[aa];W[ac])
(;B[ef];W[ac];B[ae];W[aa]))
(;B[ba];W[bb];B[ac];W[aa];B[ab];W[ac])
(;B[ac];W[bb]
(;B[ba];W[aa];B[ab];W[ac])
(;B[ae];W[ba]))
(;B[ca];W[bb]
(;B[ba];W[aa];B[ba];W[ac])
(;B[ac];W[aa]))
(;B[aa];W[bb]
(;B[ac];W[ba])
(;B[ba];W[ac]))
(;B[ae];W[bb];B[ba];W[ac]C[Seki.]))