(;AB[ac]AB[bc]AB[cc]AB[dc]AB[ec]AB[fb]AB[ea]AW[ad]AW[bd]AW[cd]AW[dd]AW[ed]AW[fc]AW[gb]AW[fa]AW[ga]AW[gd]MA[fa]C[Maybe you thought the corner was safe, even counting some points there. Then White played F19 and suddenly you're not so sure. How much can you salvage?]AP[goproblems]
(;B[ba]
(;W[eb]
(;B[da];W[db]
(;B[cb];W[ca]
(;B[ab]C[Black has 2 points in gote while White has 4 points. Either side can get another point by playing D1. This is far worse than the solution. Thanks to MeleeNewb for fixing a problem that's just 5 minutes old...!])
(;B[da];W[ab]))
(;B[ab];W[cb])
(;B[ca];W[ab]))
(;B[ab];W[db]
(;B[cb]C[Just 2 points in gote white White gained at least 3 points. Net result -1 point to Black or worse.])
(;B[ca];W[cb])
(;B[da];W[cb]))
(;B[db]
(;W[ab]
(;B[bb];W[da];B[ca]C[Black lives with 4 points in gote, White still needs to defend to get up to 3 points. So the result is at least +1 point to Black.RIGHT])
(;B[fb];W[bb]
(;B[cb];W[eb]C[Ko. Black cannot play D19 (self-atari).])
(;B[da];W[cb]C[Dead.])
(;B[eb];W[cb]
(;B[ca];W[da])
(;B[aa];W[da])
(;B[da];W[ca]))
(;B[ca];W[eb]C[Ko])
(;B[aa];W[ca]))
(;B[da])
(;B[cb];W[da])
(;B[ca];W[bb];B[fb]C[Ko]))
(;W[da];B[ca]C[At least +1 to Black.RIGHT]))
(;B[cb];W[da];B[ab]C[Just 2 points in gote while White gained at least 3 points.])
(;B[ca];W[db]
(;B[cb];W[ab])
(;B[ab];W[cb])
(;B[da];W[ab]))
(;B[bb];W[db]))
(;W[cb];B[db]C[Black gets at least 5 points more than White.RIGHT])
(;W[db];B[eb]C[+8 points. White won't play this way.RIGHT])
(;W[da];B[eb]C[+8 points to Black.RIGHT])
(;W[ca];B[da]C[Black gets at least 5 points more than White.RIGHT])
(;W[bb]
(;B[da]
(;W[eb]
(;B[cb]C[+4 points to Black.RIGHT])
(;B[db];W[ab]))
(;W[ab];B[cb];W[eb];B[aa];W[fb];B[db]C[+4 points to Black. Note that the whole sequence is forced.RIGHT]))
(;B[cb];W[eb];B[da]C[+4 to BlackRIGHT]))
(;W[ab];B[eb]C[+8 to BlackRIGHT]))
(;B[eb];W[cb]
(;B[ba];W[bb]
(;B[ab];W[ca]C[10000 year ko. Whoever wants to win it needs 2 external threats, though White can make it seki by connecting the ko.])
(;B[da];W[ca];B[ab];W[aa]C[Ko])
(;B[ca];W[ab];B[da]C[Gote seki, just not good enough.]))
(;B[bb];W[ba]
(;B[da];W[ab]C[Ko. Black cannot play C19 or D18 (self-atari ).])
(;B[ca];W[da]
(;B[db];W[ab])
(;B[aa];W[ab]C[Ko])
(;B[ab]C[Black dies in gote. This is no seki: White can fill C19 and atari with D17. If Black captures White plays C19 again, so Black has just one eye.]))
(;B[db])
(;B[ab])
(;B[aa];W[ca]C[10000 year ko. Whoever wants to win it needs 2 external threats, though White can make it seki by connecting the ko.]))
(;B[ab];W[ca]
(;B[ba];W[bb]C[10000 year ko. Whoever wants to win it needs 2 external threats, though White can make it seki by connecting the ko.])
(;B[bb];W[ba];B[da]C[Gote seki, just not good enough.]))
(;B[ca];W[ba]
(;B[da];W[ab])
(;B[bb];W[da]
(;B[db];W[ab])
(;B[aa];W[ab]C[Ko])
(;B[ab]C[Black dies in gote. This is no seki: White can fill C19 and atari with D17. If Black captures White plays C19 again, so Black has just one eye.]))
(;B[db]
(;W[da]C[Ko])
(;W[bb]))
(;B[ab];W[da]))
(;B[db];W[bb]
(;B[ca];W[ab])
(;B[ab];W[ca];B[ba];W[aa]C[Ko])
(;B[ba];W[ab]
(;B[ca];W[da])
(;B[aa];W[da])
(;B[da];W[ca]))
(;B[aa];W[ab]))
(;B[da];W[ba]
(;B[ca];W[ab])
(;B[bb];W[ab]C[Ko. Black cannot play C19 or D18 (self atari).])
(;B[db];W[ab])
(;B[ab];W[bb];B[ca]C[Gote seki. Just not good enough.])
(;B[aa];W[bb]))
(;B[aa];W[ba]
(;B[da];W[bb])
(;B[ab];W[da])
(;B[bb];W[ca]C[10000 year ko. Whoever wants to win it needs 2 external threats, though White can make it seki by connecting the ko.])))
(;B[db];W[ca]
(;B[da];W[bb]
(;B[cb];W[ba])
(;B[ab];W[ba])
(;B[ba];W[aa]))
(;B[bb];W[da]
(;B[eb];W[ba]
(;B[aa];W[ab]C[Ko])
(;B[cb];W[ab]))
(;B[ba];W[eb])
(;B[cb];W[eb])
(;B[aa];W[eb]))
(;B[eb];W[bb])
(;B[ba];W[bb]
(;B[ab];W[aa]C[Ko])
(;B[cb];W[aa])
(;B[da];W[aa])
(;B[eb];W[aa])
(;B[aa];W[ab]))
(;B[cb];W[bb]
(;B[da];W[ba])
(;B[ba];W[aa])
(;B[ab];W[ba])
(;B[aa];W[ba])
(;B[eb];W[ab]))
(;B[ab];W[ba]))
(;B[da];W[eb]
(;B[cb];W[ba])
(;B[bb];W[db])
(;B[ba];W[db]
(;B[cb];W[ca]
(;B[ab]C[Black has 2 points in gote while White has 4 points. Either side can get another point by playing D1. This is far worse than the solution. Thanks to MeleeNewb for fixing a problem that's just 5 minutes old...!])
(;B[da];W[ab]))
(;B[ab])
(;B[ca]))
(;B[ca];W[bb])
(;B[db];W[bb]
(;B[ba];W[ab])
(;B[fb];W[ba])))
(;B[cb];W[eb]
(;B[ba];W[da];B[ab]C[Just 2 points in gote while White gained at least 3 points.])
(;B[ab];W[ba])
(;B[da];W[ba])
(;B[db];W[ba]
(;B[fb];W[ca];B[aa];W[bb]C[Just one eye.])
(;B[bb]
(;W[da]
(;B[ca];W[ab])
(;B[aa];W[ab]))
(;W[aa];B[fb];W[ca])))
(;B[bb];W[da]))
(;B[ca];W[eb]
(;B[db];W[bb]
(;B[fb]C[Ko])
(;B[ba];W[ab];B[fb]C[Ko])
(;B[ab];W[ba]C[Ko]))
(;B[bb];W[db]))
(;B[bb])
(;B[ab]
(;W[eb]
(;B[ba];W[db]
(;B[cb]C[Just 2 points in gote white White gained at least 3 points. Net result -1 point to Black or worse.])
(;B[ca];W[cb])
(;B[da];W[cb]))
(;B[cb];W[ba])
(;B[ca];W[db])
(;B[da];W[ba])
(;B[bb];W[db])
(;B[db]
(;W[ca]
(;B[fb];W[ba])
(;B[da];W[ba])
(;B[ba]))
(;W[ba]
(;B[ca];W[bb]C[Ko])
(;B[fb];W[ca]))))
(;W[ba];B[eb];W[cb];B[da];W[bb];B[ca]C[Gote seki. Just not good enough.])
(;W[da];B[eb];W[ba]))
(;B[aa];W[eb]
(;B[bb];W[ca])
(;B[ca];W[bb])
(;B[db];W[da]
(;B[ca];W[bb])
(;B[bb];W[ca]))
(;B[cb];W[da])
(;B[da];W[db])
(;B[ba];W[db])))