Variations of Our Solution (IIIa)
No Early Kikashi
VAR (.1)
: ( 648aa) Please note that this move is played outside the Main Semeai, but does not lose a tempo therein, because becomes an approach-move liberty of White's group at the left. Black is still par with the Punishment Semeai Liberty Level. | |
Black is unable to continue with , or , in the left centre, because any of these moves would push him below the Punishment Semeai Liberty Level. Black is strictly bound to continue with the Main Semeai. Therefore, giving atari at is his only choice, because this move is the only one that also defends against White's cut at (which White will not play now; please refer to this subvariation 648of for details). White will connect at , providing Black with two Main Semeai Liberties. Now, Black is able to defend against White's cut at . We ask for your kind understanding that we felt unable to adjust the move numbers (i.e. to increase these by two) in the many already created diagrams, which follow in this part of the variation tree. | |
: (A 648mm) White will win this ko anyway, so Black can simplify the issue by retreating to , instead. Black's atari is played outside the Main Semeai, and so loses a tempo therein. | |
: Again, her move is played outside the Main Semeai, but creates another approach-move liberty for her left hand group at C. White does not lose a tempo. | |
(Referenced by 648cy) : (A 648ms; B 648mz) As two moves earlier, he might retreat with , instead. Black's move is played outside the Main Semeai, and so loses a tempo, in principle. However, White's two approach-move liberties vanished with this move, so the net effect on the Main Semeai Liberties is plus one. | |
: Black is at nine Main Semeai Liberties now. Winning the ko will require two White moves at (capture), and at (connect). Both of White's approach-move liberties will become effective again, so the net effect on the Main Semeai is zero. Black, however, will lose a tempo in the Main Semeai by his connection at , should he be able to win the ko. Please note that - from now on - we will not update the board's border colour after moves that capture the ko in the left centre, as long as this ko fight is still active, and undecided. | |
: (136 648na) Before finding our earlier mistake with playing White's kikashi , in the centre too early, Dany questioned, whether it might be feasible to generate an additional White ko threat by splitting the Nakade Sequence here. But our deeper analysis showed that it is not! | |
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: (A 648nc; 141 648nd) Counter-intuitively, it will be worse for her to block at , instead, erasing several potential Black ko threats at the top. : | |
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; : (A 648qa) We now know that White's atari in the upper left centre cannot be counted as an additional ko threat. While working on another topic, Joachim discovered by the way that White's push at – that has used by us for so long as a ko threat – does not include a sufficient threat, which would enforce an immediate local reply by Black. In the subvariation, we will use White's push at the left edge, instead, to explain Joachim's finding in detail. |
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: : (A 648ne) It will not make a difference, if she captures at , instead. Thereafter, Black has the atari at as a ko threat. |
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: : : (168 648nf) Connecting the ko in the centre, instead, will be a grave mistake. : |
: Compared to White's territory-reducing (in the Capture Variation) ko threat at (Black would answer at ), White's ko threat in the centre does not affect the score of the game here. However, please be very well aware that the above is true, only if Black does not have a valid ko threat left (outside the Main Semeai area) that he could use with Joachim's Final Ko in the Semeai Variation ( 648ag). | |
: Joachim found that Black's throw-in at in the upper right were a valid ko threat. White is barely ahead in ko threats (, vs. ), so our earlier mistake does not affect the outcome of the game. White will still win the ko fight, even with one effective ko threat less. : Otherwise, Black will recapture the ko soon, and connect thereafter, gaining an advantage of two points in the Semeai Variation. : | |
Black plays 1/3 reductions. Before the end of the game, Black will have to capture at . | |
Capture Variation: Compared to the superordinate variation ...
In total, gains and losses compensate for each other. White + 2 => White + 2 | |
Semeai Variation: Compared to the superordinate variation ...
In total, White gained six points. Black + 4 => White + 2 | |