(;AW[cb]AW[dc]AW[dd]AW[cd]AW[bd]AB[ad]AB[ae]AB[be]AB[ce]AB[ee]AB[ed]AB[ec]AB[eb]AB[db]C[White to struggle for life in the corner! White has no ko threats.]AB[df]AP[goproblems] (;W[bc] (;B[ac]C[CHOICE] (;W[ab] (;B[ca]C[CHOICE] (;W[ba]C[White's stones in the corner have just barely enough liberties to form three eyes. The 'false eye' warning signal with Black occupying two diagonals at B18's eye is irrelevant; White has two true eyes at A19 and C17.RIGHT]) (;W[aa];B[ba]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[bb];B[ba]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[cc];B[ba]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[da];B[ba] (;W[bb];B[ea]C[White's attempt at grabbing eyespace in the corner was unsuccessful, and Black can connect with D19. White can try to play a ko threat at A19 but Black can simply ignore this; White capturing with D19 will allow Black to throw in again with C19 and destroy White's remaining eyespace.]) (;W[aa];B[bb] (;W[ab];B[ea]C[White's attempt at a snapback is unsuccessful. Black destroys White's corner eyespace and will connect with D19.]) (;W[aa];B[ab]C[White's attempts to capture Black's invading stones are unsuccessful and Black connects.])) (;W[cc];B[de]C[White fills up their own eyespace and allows Black to atari White with no hopes of escape. Even if White captures B19 and C19, Black can simply ignore this. White still does not have enough space for two eyes in the corner.]))) (;B[ba]C[CHOICE] (;W[ca]C[White can tenuki in this position. If Black attempts to capture the A18 stone, White can simply snapback.RIGHT]) (;W[bb];B[ca]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[aa];B[ca]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[cc];B[ca]C[Black destroys White's corner eyespace and will connect with D19.]) (;W[da];B[ca] (;W[bb];B[ea]C[White's attempt at grabbing eyespace in the corner was unsuccessful, and Black can connect with D19. White can try to play a ko threat at A19 but Black can simply ignore this; White capturing with D19 will allow Black to throw in again with C19 and destroy White's remaining eyespace.]) (;W[aa];B[bb] (;W[ab];B[ea]C[White's attempt at a snapback is unsuccessful. Black destroys White's corner eyespace and will connect with D19.]) (;W[aa];B[ab]C[White's attempts to capture Black's invading stones are unsuccessful and Black connects.])) (;W[cc];B[de]C[White fills up their own eyespace and allows Black to atari White with no hopes of escape. Even if White captures B19 and C19, Black can simply ignore this. White still does not have enough space for two eyes in the corner.])))) (;W[bb];B[ab]C[White does not have enough space to form a real eye in the corner.]) (;W[ca];B[ab]C[White does not have enough space to form a real eye in the corner.]) (;W[ba];B[ab]C[White does not have enough space to form a real eye in the corner.]) (;W[aa];B[ab]C[White does not have enough space to form a real eye in the corner.]) (;W[cc];B[ab]C[White does not have enough space to form a real eye in the corner. Connecting at C17 only destroys White's eyespace.]) (;W[da];B[ab]C[White does not have enough space to form a real eye in the corner. The move D19 does not gain any extra breathing room; White must still connect this stone with C19.])) (;B[ab]C[CHOICE] (;W[ac] (;B[bb]C[CHOICE] (;W[aa] (;B[ba]C[CHOICE];W[ca];B[da];W[aa]C[Even though Black managed to gain an eye in the corner it was not enough to stop White from capturing and creating a second eye.RIGHT]) (;B[ca]C[CHOICE];W[ba];B[da]C[Black was unable to destroy White's corner eyespace. Black does have a ko threat on A18 or B18 in the future but White survives.RIGHT]) (;B[de]C[CHOICE];W[ba]C[Black's attempting at destroying White's eyespace in the corner is unsuccessful and White has enough space to connect while maintaining two real eyes.RIGHT])) (;W[ba];B[de]C[] (;W[aa]C[Black's attempting at destroying White's eyespace in the corner is unsuccessful and White has enough space to connect while maintaining two real eyes.RIGHT]) (;W[ca];B[cc]C[White was put into atari and did not give themself more liberties.]) (;W[cc];B[ca]C[White was put into atari and connecting does not give them more liberties. It only destroys the eyespace on C17.]) (;W[da];B[cc]C[White was put into atari and did not give themself more liberties.])) (;W[ca];B[de] (;W[ba];B[cc]C[White was put into atari and did not give themself more liberties.]) (;W[cc];B[da]C[White was put into atari and did not give themself more liberties. Connecting only fills up the eyespace on C17.])) (;W[cc];B[ca]C[White fills up their own eyespace on C17 and allows Black to atari. White has no hopes of gaining more liberties.]) (;W[da];B[de]C[White is put into atari with no way of gaining extra liberties. The move D19 does not gain any extra breathing room; White must still connect this stone with C19. White does have a ko threat at B19 for life if Black does not capture right away. However, White can do better in this problem.])) (;B[ba]C[CHOICE] (;W[ca]C[Black's attempts at destroying the corner were unsuccessful and White can survive. White can tenuki if Black attempts to approach further.RIGHT]) (;W[bb];B[ca]C[White allows Black to invade too far and destroy White's eyespace in the corner. Black will connect at D19. White playing A19 is not a ko for life because it must be filled to connect and White will only have one eye.]) (;W[da];B[ca]C[White allows Black to invade too far and destroy White's eyespace in the corner. Black will connect at D19. White capturing the A18 stone with A19 is not a ko for life because it must be filled to connect and White will only have one eye on C17.]) (;W[cc]C[White has filled up their own C17 eyespace and Black can tenuki. The remaining area in the corner is a well-known dead eyespace (although White can possibly use it as ko threats in the future)])) (;B[ca]C[CHOICE] (;W[ba]C[White does not have to play B18 to connect, White can and should tenuki with sente if Black continues to approach in this corner. Even if Black captures the White stone on B19, White can snapback by taking with B19 again.RIGHT]) (;W[bb];B[ba]C[White allows Black to invade too far and destroy White's eyespace in the corner. Black will connect at D19. White playing A19 is not a ko for life because it must be filled to connect and White will only have one eye.]) (;W[cc];B[de]C[White has filled up his own eyespace on C17 and allows Black to atari White. White has no chance of escaping.]) (;W[aa];B[ba]C[White was unable to capture the A18 stone and Black has destroyed too much of White's corner eyespace. Black will connect at D19.]))) (;W[bb];B[ac]C[White does not have enough space to form a real eye in the corner.]) (;W[ba];B[ac]C[Black connects and White does not have enough space to form a real eye in the corner.]) (;W[ca];B[ac]C[Black connects and White does not have enough space to form a real eye in the corner.]) (;W[aa];B[ac]C[Black simply connects instead of taking with B19, which leaves some potential aji. White does not have enough space to form a real eye in the corner.]) (;W[cc];B[ac]C[White does not have enough space to form a real eye in the corner. Connecting at C17 only destroys White's eyespace.]) (;W[da];B[ac]C[White does not have enough space to form a real eye in the corner. The move D19 does not gain any extra breathing room; White must still connect this stone with C19.])) (;B[ba]C[CHOICE] (;W[ca];B[ab];W[ac]C[Black's attempts at destroying the corner were unsuccessful and White can survive. White can tenuki if Black attempts to approach further.RIGHT]) (;W[bb];B[ca]C[White has allowed Black to invade and White no longer has enough space to create a second eye. Black will connect at D19.]) (;W[ac];B[ca]C[White has allowed Black to invade and White no longer has enough space to create a second eye. Black will connect at D19.]) (;W[ab];B[ca]C[White has allowed Black to invade and White no longer has enough space to create a second eye. Black will connect at D19.]) (;W[aa];B[ca]C[White has allowed Black to invade and White no longer has enough space to create a second eye. Black will connect at D19.]) (;W[cc];B[ca]C[White has filled up their own eyespace and allowed Black to invade. White no longer has enough space to create any real eyes and Black will connect at D19.]) (;W[da];B[ca]C[White has allowed Black to invade and White no longer has enough space to create a second eye. Black will capture with E19 and is able to connect at D19.])) (;B[ca]C[CHOICE];W[ba] (;B[ab]C[CHOICE] (;W[ac]C[White does not have to play B18 to connect, White can and should tenuki with sente if Black continues to approach in this corner. Even if Black captures the White stone on B19, White can snapback by taking with B19 again.RIGHT]) (;W[bb];B[ac]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. White capturing on C19 can only create a false eye.]) (;W[aa];B[bb] (;W[ac];B[ba]C[White has allowed Black to destroy White's corner eyespace and Black will connect at D19.]) (;W[ba];B[ac]C[White has allowed Black to invade too far and destroy White's corner eyespace. White capturing on C19 will only create a false eye.]) (;W[aa];B[ac]C[White has allowed Black to invade too far and destroy White's corner eyespace.]) (;W[cc];B[ac]C[White has filled up their own eyespace and allowed Black to put White into atari with no hopes of escape.]) (;W[da];B[ac]C[White has allowed Black to invade too far and destroy White's corner eyespace. White capturing on C19 will only create a false eye.])) (;W[da];B[ac]C[White has allowed Black to invade and White no longer has enough space to create a second eye.]) (;W[cc];B[ac]C[White filled up his own eyespace and allowed Black to connect. White no longer has enough space to create any real eyes.])) (;B[ac]C[CHOICE];W[ab]C[White's stones in the corner have just barely enough liberties to form three eyes. The 'false eye' warning signal with Black occupying two diagonals at B18's eye is irrelevant; White has two true eyes at A19 and C17.RIGHT])) (;B[bb]C[CHOICE] (;W[ba] (;B[ac]C[CHOICE] (;W[ab]C[White has stopped Black's invasion and has created three eyes in the corner. White can immediately tenuki if Black tries to invade further with D19 and C19; all of White's stones are perfectly safe. There are no aji or ko threats against White.RIGHT]) (;W[aa];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[ca];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[cc];B[ab]C[White has filled their own eyespace on C17 and allowed Black to invade the corner. White cannot make any eyes.]) (;W[da];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye. D19 only makes a false eye as well.])) (;B[ab]C[CHOICE] (;W[ac]C[RIGHT];B[de]C[] (;W[aa]C[Black's attempting at destroying White's eyespace in the corner is unsuccessful and White has enough space to connect while maintaining two real eyes.RIGHT]) (;W[ca];B[cc]C[White was put into atari and did not give themself more liberties.]) (;W[cc];B[ca]C[White was put into atari and connecting does not give them more liberties. It only destroys the eyespace on C17.]) (;W[da];B[cc]C[White was put into atari and did not give themself more liberties.])) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[ca];B[ac]) (;W[cc];B[ac]C[White has filled their own eyespace on C17 and allowed Black to invade the corner. White cannot make any eyes.]))) (;W[ab] (;B[ba]C[CHOICE] (;W[ca]C[Black's attempt to destroy corner eyespace has failed and White will live with two eyes. Even if Black captures the A18 stone, White can simply recapture with snapback.RIGHT]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[ac];B[ca]C[White has allowed Black to invade the corner and turn C17 into a false eye. Black will connect at D19.]) (;W[da];B[ea]C[White does not have time to capture the Black invader stones. White is in atari and connecting still leaves White in atari. After Black captures he will be able to connect on D19.]) (;W[cc]C[White has filled up their own eyespace on C17. Black is actually able to tenuki here; even if White captures the Black invading stones there is only enough space for one eye.])) (;B[ca]C[CHOICE] (;W[ba]C[White has created three eyes and is unconditionally alive. White can immediately tenuki if Black saves his C19 stone and can further tenuki if Black further approaches at A17. This shape is completely safe with no aji or ko threats against White.RIGHT]) (;W[ac];B[ba]C[Black has turned C17 into a false eye and can simply connect with D19.]) (;W[aa];B[cc]C[Blak can simply cut off white with A17, and if White blocks by playing there, Black connects with C18 and destroys White's eyespace.])) (;B[ac]C[CHOICE] (;W[ba]C[White has stopped Black's invasion and has created three eyes in the corner. White can immediately tenuki if Black tries to invade further with D19 and C19; all of White's stones are perfectly safe. There are no aji or ko threats against White.RIGHT]) (;W[aa];B[ba]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[ca];B[aa]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye. Black can connect at A18.]) (;W[cc];B[aa]C[White has filled their own eye on C17 and allowed Black to destroy the corner eyespace.]))) (;W[ac];B[ba] (;W[ca];B[da]C[White has allowed Black to atari the C19 and C18 stones. If White connects and fills up the C17 eyespace, the remaining area in the corner is a dead shape.]) (;W[ab];B[ca]C[White has allowed Black to invade the corner and turn C17 into a false eye. Black will connect at D19.]) (;W[da];B[ca]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[cc];B[ca]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[aa];B[ca]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.])) (;W[ca];B[ac] (;W[ab];B[aa]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye. Black can connect at A18.]) (;W[ba];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[aa];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye.]) (;W[cc];B[ab]C[White has filled in their own eyespace on C17 and allowed Black to destroy the corner eyespace.])) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye. Black will connect at A18 or capture White's stone at B18 if White tries to block.]) (;W[cc];B[ca] (;W[ab];B[ba]C[White has filled up their own C17 eye and allowed Black to invade and destroy White's corner eyespace. Black can connect at D19.]) (;W[ac];B[ab]C[White has allowed Black to invade and put White into atari with no ways of gaining extra liberties.]) (;W[ba];B[aa]C[White has filled up their own eye and allowed Black to destroy the corner eyespace. Black can connect at B19 and D19.]) (;W[aa];B[ba]C[White has filled up their own eye and allowed Black to destroy the corner eyespace. Black can connect at D19.]) (;W[da];B[ea]C[White has filled up their own eye and allowed Black to destroy the corner eyespace. Black can connect at B19 and D19.])) (;W[da];B[ac];W[ba];B[ab]C[White has allowed Black to invade and destroy White's corner eyespace as well as making C17 a false eye. D19 only makes a false eye as well.]))) (;W[bb];B[bc] (;W[ab];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[ac];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[cc];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[aa];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White does not have enough space to form two eyes in the corner.]) (;W[ba];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White does not have enough space for two real eyes.]) (;W[ca];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[da];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner. D19 does not give White any extra breathing room; C19 must still be played to connect the D19 stone.])) (;W[ab];B[bc] (;W[ac];B[ca] (;W[ba];B[de]C[White does not have time to capture the C19 stone and connect; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form two eyes in the corner. If White sacrifices the four stones and captures with D19, C19 is a false eye. White must fill that space to connect the D19 stone.]) (;W[bb];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White does not have enough space to form two eyes.]) (;W[cc];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White does not have enough space to form two eyes.]) (;W[aa];B[de]C[White does not have time to capture the B17 stone; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form any eyes in the corner.]) (;W[da];B[ea] (;W[bb];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White only has enough space for one eye.]) (;W[cc];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White only has enough space for one eye.]) (;W[ba];B[de]C[White does not have time to capture the B17 or C19 stones; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form two eyes in the corner.]) (;W[aa];B[de]C[White does not have time to capture the B17 stone; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form any eyes in the corner.]))) (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[ba];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner.]) (;W[ca];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner.]) (;W[cc];B[ac]C[White has filled up his own C17 eyespace and allowed Black to invade. White only has enough space for one eye in the corner.]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for two eyes in the corner.]) (;W[da];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect this stone.])) (;W[ac];B[bc] (;W[bb];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[ab];B[ca] (;W[ba];B[de]C[White does not have time to capture the C19 stone and connect; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form two eyes in the corner. If White sacrifices the four stones and captures with D19, C19 is a false eye. White must fill that space to connect the D19 stone.]) (;W[bb];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White does not have enough space to form two eyes.]) (;W[cc];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White does not have enough space to form two eyes.]) (;W[aa];B[de]C[White does not have time to capture the B17 stone; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form any eyes in the corner.]) (;W[da];B[ea] (;W[bb];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White only has enough space for one eye.]) (;W[cc];B[ba]C[White has allowed Black to invade too far and has destroyed White's corner eyespace. Black can connect at D19 and White only has enough space for one eye.]) (;W[ba];B[de]C[White does not have time to capture the B17 or C19 stones; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form two eyes in the corner.]) (;W[aa];B[de]C[White does not have time to capture the B17 stone; White is in atari and connecting at C17 still leaves White in atari. White does not have enough space to form any eyes in the corner.]))) (;W[ba];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[aa];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[ca];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[cc];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[da];B[ab]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect this stone. Black can play A17 to connect.])) (;W[ca];B[bc] (;W[ab];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner.]) (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[cc];B[ab]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. Black can play A17 to connect.]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ba];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ac];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.])) (;W[cc];B[bc] (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner.]) (;W[ab];B[ac]C[White has filled up his own C17 eyespace and allowed Black to invade. White only has enough space for one eye in the corner.]) (;W[ca];B[ab]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. Black can play A17 to connect.]) (;W[ba];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ac];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[da];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect.])) (;W[ba];B[bc] (;W[ab];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner.]) (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White does not have enough space for two real eyes.]) (;W[ac];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ca];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[da];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. C19 is a false eye; White must fill the eye to connect the D19 stone.]) (;W[cc];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.])) (;W[aa];B[bc] (;W[ac];B[ab]C[Black has invaded too far and destroyed White's C17 eyespace. Black will connect at A17 and White cannot form any real eyes.]) (;W[ab];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for two eyes in the corner.]) (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White does not have enough space to form two eyes in the corner.]) (;W[ba];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ca];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[da];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for two eyes in the corner.])) (;W[da];B[bc] (;W[cc];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect.]) (;W[ac];B[ab]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect this stone. Black can play A17 to connect.]) (;W[ab];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White only has enough space for one eye in the corner. D19 does not give White any extra breathing room; White must still play C19 to connect this stone.]) (;W[bb];B[ac]C[Black has invaded too far and destroyed White's C17 eyespace. White can only form one real eye in the corner. D19 does not give White any extra breathing room; C19 must still be played to connect the D19 stone.]) (;W[ca];B[ab]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner.]) (;W[ba];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for eyes in the corner. C19 is a false eye; White must fill the eye to connect the D19 stone.]) (;W[aa];B[ac]C[White has allowed Black to invade and destroy White's C17 eyespace. White does not have enough space for two eyes in the corner.])))