Problem No. 120 from Igo Hatsuyoron
By Inoue Dosetsu Inseki (1646 - 1719)
Black to play and win |
Black to play and win |
Move | Variation | Result | ||
Second throw-in. | See next summary. | |||
In the lower right corner. | See | |||
At the 2-1-point of the lower right corner. | ||||
At the 1-2-point in the lower right corner and ... | ||||
... running out. | ||||
... capture of three stones. | ||||
Capture of three stones. | ||||
Atari from the outside. | ||||
Geta. | ||||
Attempt to block and ... | ||||
... capture of three stones. | ||||
... reducing liberties. | ||||
Attempt to block and reducing liberties. | ||||
Attempt to block and playing Ko. | ||||
Reducing liberties. | ||||
Capture of three stones. | ||||
Capture of twenty stones. | ||||
Capture in the lower left. | ||||
Attempt to connect on the third line. | ||||
Dango attempt. | ||||
Throw-in. | ||||
Throw in below or placement inside. | ||||
Push into the top right corner. | ||||
Capture of three stones. | ||||
Endgame on the left side. | ||||
Without | ||||
Reducing liberties. | ||||
Osae in the upper left. | ||||
Attempt to cut. | ||||
Save one stone in the lower left. | ||||
Another Sente in the centre. | ||||
No connection. | ||||
This SGF-file (as of 2009-06-02) contains most of the sequences shown here. I'm sorry, but the commentary is available in English only. |
B 19: Throwing in for the second time is said to be not a good idea. |
Dia. 19.1: B 19 - W 20 |
B 21: Black has to prevent a White eye, thus filling in a very important liberty (which in the current opinion would be necessary in a Semeai later on). [ see explanation ] |
Dia. 19.2: B 21 - W 22 |
W 24: There are no statements about this variation in the sources at my disposal. The commentary here was worked out together with Joachim Meinhardt. B 25: The Black answer is forced. B 27: It is best for Black to follow the known course of the Main Path here. To capture the three white stones instead will be far more time-consuming. |
Dia. 24.1: W 24 - W 28 |
B 29: Black can immediately attack the white group in the corner with this move. Perhaps it will be more elegant to continue with 30 before. |
Dia. 24.2: B 29 - W 32 |
Dia. 24.3: B 33 |
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Dia. 24.4: W 34 - W 36 |
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B 37: Black wins the Semeai in the corner by one move and so the game. |
Dia. 24.5: B 37 |
B 29: Blacks sacrifices a second stone in the centre. B 31: Again Black starts the Semeai in the corner. He could follow the Main Path for a while, too, beginning with 31 at 32, but this would result only in giving away more stones to White. |
Dia. 24.6: B 29 - W 34 |
Dia. 24.7: B 35 |
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B 37: Black can play Tenuki once in the lower right and remains one step faster there. Black wins the game. |
Dia. 24.8: W 36 - B 39 |
B 31: At any time Black can interrupt his flight along the Main Path and capture the white group in the lower right corner. |
Dia. 24.9: B 27 - W 36 |
Dia. 24.10: B 37 - W 46 |
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Dia. 24.11: B 47 - W 56 |
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Dia. 24.12: B 57 - W 66 |
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B 67: But waiting until the Atari of 67 has been one move too long. Black's last chance has been after White 66. W 68: This is why White takes the black stones in the centre off the board, before Black played the move in the corner. |
Dia. 24.13: B 67 - W 68 |
B 69: Black recaptures. |
Dia. 24.14: B 69 |
W 70: White makes a placement, as usual. B 73: The specific characteristic of this corner causes Black difficulties in approaching the White stones. |
Dia. 24.15: W 70 - W 74 |
W 76: Different from the Main Path White here is the decisive step faster. White gets the whole right side and wins the game. |
Dia. 24.16: B 75 - W 76 |
B 27: Second possibility for Black is to capture the three white stones. But the following sequence will be much longer than the one shown before. Above this move is possible at any time between Black 29 and Black 67, but these variations are more likely to belong herein as a change in the order of moves. |
Dia. 24.17: B 27 |
W 28: White must prevent two Black eyes. After that move the journey starts that is explained in detail in the Main Path. |
Dia. 24.18: W 28 - B 37 |
Dias. ... |
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B 67: Or Black captures the three white stones in the lower right at least with this move. Now the Main Path follows in principle. |
Dia. 24.19: B 67 |
Dia. 24.20: W 68 - B 77 |
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Dia. 24.21: W 78 - W 86 |
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Dia. 24.22: B 87 - W 96 |
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Dia. 24.23: B 97 - W 106 |
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Dia. 24.24: B 107 - W 116 |
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Dia. 24.25: B 117 - W 124 |
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Dia. 24.26: B 125 - W 132 |
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Dia. 24.27: B 133 - W 142 |
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Dia. 24.28: B 143 - W 152 |
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Dia. 24.29: B 153 - W 158 |
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Dia. 24.30: B 159 - W 170 |
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B 171: As in the Main Path, Black again gets the White stones in the lower right corner. |
Dia. 24.31: B 171 |
Dia. 24.32: The End of this Variation. |
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Black wins by two points. | Dia. 24.33: The Score. |
W 62: White tries to get a Ko. (Moves not shown in the diagrams here take Ko.) W 70: But she has only one internal Ko-Threat, what is not enough. |
Dia. 24.34: W 62 - B 75 |
B 79: White has no adequate Ko-Threat left, so Black will give Atari in the corner and win the Ko, wherever White plays next. |
Dia. 24.35: W 78 - B 79 |
Variation for W 42 |
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W 50: Blocking with White 50 leads to a similar result as blocking with White 44. |
Dia. 50.1: W 50 - B 55 |
W 60: White blocks Blacks path. B 61: Black captures the single White stone and gets an additional liberty, which enables him to capture three White stones with 63. Because White is hindered to occupy each of the two liberties of the chain of Black stones in the centre immediately, this seems to be a little bit like the variation for W 42. |
Dia. 60.1: W 60 - B 63 |
Dia. 60.2: W 64 - W 68 |
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W 70: Guided by the proverb, White takes the Ko at the latest possible moment, ... B 71: ... but Black has two liberties left. |
Dia. 60.3: B 69 - B 71 |
B 73: Finally, Black takes the Ko back. On the whole board there are no adequate Ko-Threats for White. So Black will be able to capture the White stones in the lower right corner with A, giving White two moves in a row wherever she likes. |
Dia. 60.4: W 72 - B 73 |
B 131: Even now Black will not be successful after capturing the three White stones inside his belly. |
Dia. 131.1: B 131 |
W 134: White must plaque the Black centre group to be successful here. If she otherwise continues to take liberties of the Black group in the upper right, Black would win with three points (it would result a change in the order of moves with the variation for W 132). |
Dia. 131.2: W 132 - W 138 |
Dia. 131.3: B 139 - W 140 |
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B 141: If Black captures the White stones on the left, White gets two eyes on the right with 142 and wins the game with ease. |
Dia. 131.4: B 141 - W 142 |
If Black prevents this by playing on the right side himself, White will give Atari to the Black centre group. Black is one move too late here. It is necessary for Black that he has already played a stone into the centre of the White 4-point-Nakade on the left, before he can capture the three White stones on the right with confidence. But as can be seen in the Main Path, White will not be so kind to give Black the opportunity to do so. |
Dia. 131.5: B 141 - W 142 |