Variations of Our Solution (II)
VAR (C) (B)
(Referenced by 77; 91; 128; 133; 136; 140; 152; 190; 250; 363; 380; 390; 396; 399; 818; 825; 834; 1133) : ( 219)
As shown in another sub-variation of our solution ( 555), Black cannot prevent White's large endgame in the upper left, with a move at , later. So what about trying it now, without having played the guzumi, just before the Crosscut Sequence is completed? In 2014, we finished our theoretical analysis, whether Black could successfully use the three kikashi in the top left corner (; which have been played here already) as ko-threats, when he keeps them in reserve. Following our final conclusion ( 873), these potential three ko-threats cannot be counted independently on their own, so these will have no effect on the outcome of the game. An exemplary application case can also be found earlier in this book ( 83). |
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: (A 236; B 237) If White wanted to pre-empt Black from forcing her to start the forthcoming ko-semeai on the right side "early", she would have to insert the kikashi in the top left corner first, starting with the atari of - this will stop Black from taking that point later ( 257). However, Black's shape in the upper left will become solidified unnecessarily, providing White with some problems in finding a smooth way through the forthcoming ko-fight. |
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In the middle of 2013, when analysing the consequences of Michael Redmond's kikashi in the bamboo joint (; 838), we suddenly recognized that we previously had missed the correct moment to play this move, as a starting point to create a larger eye for Black in the upper right. We now know that one valid option for Black is to play the kikashi before the Crosscut Sequence, what is the topic of another sub-variation (71 (L); 390). |
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: (A 243; B 255; C 257) |
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: (A 270; B 283; C 284) White can neither avoid the ko with moves at , or . Then Black will play at , and get an extra liberty (the "guzumi effect"), winning him the Semeai Variation. But choosing the Capture Variation (by taking the hanezeki's tail) is no valid option for White either, because she will not get enough points on the left side, to win. |
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(Referenced by 251) : (A 285, B 286) It is also too late now to close the top left corner, with a move at , simultaneously attacking White's group on the left edge. |
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: (A 287) |
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: (86 292) This throw-in creates another false eye for White, so Black gains one move, compared to the exchange of , .
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: (A 296; B 297; C 301) Cutting immediately at , instead, is more severe, but will not help Black either. will allow White to build a larger eye, again leading to a ko-fight. |
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: (89 309) |
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: White could get more shared liberties with playing at , instead. We did not investigate this thoroughly, but we suppose that there will be no decisive effect on the main line of this sub-variation. |
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: (A 312) However, Black will get a similar result, if he does completely without this kikashi. |
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: Playing at will be worse for Black than the main line here. |
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(Referenced by 138) : (B 334; C 338) White could successfully start the ko on the right side "early", with a move at , instead. However, we tried to find a more elegant, and shorter, sequence that allows White to capture this ko as late as possible for the first time. For the resulting ko here, White uses only such moves as ko-threats, which occupy Black's liberties, and no moves that really contain a substantial, damaging, threat. White could also do without these kikashi in the top left corner, which we had thought of as a kind of precautionary measure in the very beginning of our investigation of Joachim's Ko-Semeai. As we ultimately understood in 2014 (late, but not too late), there is really no need for White to play preparatory moves in the top left corner, in order to create potential for own ko-threats in this area. |
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: (A 340) |
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: (A 345; B 346) |
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: (A 347; B 352) Please note that the exchange of / has been played already, as a mandatory requirement for White's current move. |
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: We have chosen this move for technical reasons, with regard to potential ko-threats. If Black connected at , instead, he would lose the potential ko-threat of the atari at . Additionally, White could reduce Black's eye in the centre in sente, with a move at , destroying another potential Black ko-threat (capturing two White stone inside his eye). Please note that here, in the main line, these potential Black ko-threats will not come into play. |
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: (A 356) White could also start the ko, with a move at , getting the same result as here. |
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: (A 357) As a matter of course, Black is unable to eliminate his weaknesses in the upper left corner with a move at , denying White of her potential ko-threats there. This would be equivalent to loosing a move in the semeai on the right side, giving White an unconditional win. |
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: (A 359) Again, White should not occupy an outside liberty, forcing Black to connect the hanezeki's tail. |
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(Referenced by 940) : (B 361) As already mentioned above, it will not prove advantageous for White to occupy another direct liberty, for example at , instead. She would need a really "damage threatening" ko-threat, and not liberty-occupying moves only. |
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: (A 362) Here, Black connects the hanezeki's tail, and so captures White's three stones, because his top right group has only seven liberties left. Otherwise, White would capture Black's centre group with a move at herself, thereafter winning the Punishment Semeai ( 888). Alternatively, Black could use his local ko-threat in the hanezeki, at , giving the same result. |
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(Referenced by 345) : White's group has five liberties, three shared liberties () with Black's group in the upper right, and two direct liberties (). Black's group in the lower right has five liberties, too, four direct liberties (), and one approach-move liberty (). Black's group in the upper right has seven liberties, three shared liberties () with White's group, three direct liberties (), and one approach-move liberty (). |
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