Variations of Our Solution (Ib)
KataGo's 2021 Solution
VAR (.3) (.4)
: ( 58ap) This move will increase the susceptibility to errors in the following course of the game unnecessarily (and can be a genuine mistake; 58by), and so can be considered to be a technical mistake in the timing of moves. | |
: (A 58dd) Playing tenuki to the large hiki at the top, instead, would be a grave mistake. Due to his remaining weaknesses at the left side of the board, Black would lose the game decisively. The development of the somewhat "delicate" position below is possible only after White's exchange of for . White should refrain from playing this exchange, if she does not want to continue locally immediately thereafter. : | |
: : : : However, as we will see below, there is no guarantee to deliver a flawless game thereafter. : : | |
: (Referenced by 58ct) : Please note that his move provides White with an unexpected (and new) opportunity for destroying Black's potential territory in the left centre, but which is poisoned, as we will see below. Please also note that this move is not a mistake here, despite it is played after White connected her two stones in the lower left with her previous move. Contrary to a comparable earlier subvariation ( 58ct), Black has already played the inside atari after White's crosscut in the upper left corner. : : : : | |
(Referenced by 58aa) : ( A 58dg) This alternative option is not better overall than the "usual" defense of the upper left corner (Black will be worse by four points in the Semeai Variation here, correct continuation assumed), but at least more confusing for KataGo, as it seems. : (121 58dh) I would have expected White to push at the bottom line, instead, not affecting the final scores of the game. Please remember that the marked exchange in the lower left corner was played before its time, making the position more "delicate" than necessary. : | |
: (A 58dj) Connecting her single stone in the right centre, instead, would come too early. | |
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: : (A 58dm) It would not affect the overall result of the game, if White did without this move, or played this atari later. : Please notice the (not very obvious) destructive impact of White's earlier played kikashi , on the power of her potential territory-reducing moves from the left (starting with ). : ( A 58do) White must continue with the Main Semeai, instead. : Please note that Black just won an additional tempo in the Main Semeai, which brings him to two over par, related to the Punishment Semeai Liberty Level. | |
: ; : (149 58dq) Allowing Black's forthcoming push at is quite unususal. However, it would not make a difference if White prevented this move. : Hereafter, Black is three over par, related to the Punishment Semeai Liberty Level. This implies that he has sufficient room for actions. | |
White needed five moves () to prevent all of Black moves that would reduce her territory at the top or in the upper right corner. Black needed only three moves () to defend against all White moves that would reduce his territory in the upper left and lower left corners. Therefore, a White strategy of defending weak points would not lead to success, as she has more weaknesses to cover than Black (even if we take her sente into account). Please note that White cannot stop Black from connecting his single stone in the lower right, should this become necessary. | |
A strategy of playing all destructive moves first does not make sense for White here, either, as Black has sufficient means for compensation again. White has already played three reductions, Black one. White could still play three reductions (). Currently, Black is three over par with the Punishment Semeai Level, so he could play six reductions (; connecting counts as two) thereafter. Black would be able to compensate at the right for what he lost at the left, and still keep the three surplus reductions alive, which he needs for success. | |
Black plays 3/3 reductions. | |
Capture Variation: Compared to the superordinate variation, ...
In total, White gained three points. Black + 2 => White + 1 | |
Semeai Variation: Compared to the superordinate variation, ...
In total, White gained three points. Black + 2 => White + 1 | |