New Story Line 2022
My Second Throw-in
We will shed light on the mistery of Fujisawa Hideyuki 9p rejecting a second throw-in in the hanezeki, but not be able to really penetrate to the core of his reflections. We will follow the chronological sequence of findings on this move and deduct that my Second Throw-in would not affect the relationship of liberties in the hanezeki, but benefit Black territorially in both Main Variations. Choosing Harry's Hasami-Tsuke Sequence for the reduction of White's upper left corner in due time would not only increase Black's flexibility in the game, but also affect the overall result, as KataGo discovered. Black would be able to benefit by another point overall. | |
Referenced by ( 2022MainLine) Let's go back to the dawn of time ... | |
: ( 2022MainLine) Black can do so in sente, as Black threatens to exploit White's shortage of liberties with , , , aiming at a snap-back. Black's connection defends against the forcing sequence (threatens to create an eye), , , , which White would otherwise play at the earliest possible moment, and which would take Black's large group a decisive Main Semeai Liberty. | |
: This move stops Black from playing my Second Throw-in , which will be explained in detail below, later in the game. In principle, White might alternatively fill the other false eye at , as Fujisawa Hideyuki rejected my Second Throw-in anyway. | |
Decades later, in the world of amateurs ... | |
: In his commentary, Fujisawa Hideyuki unfortunately did not elaborate in detail on what was the actual reason for his rejection of this move. However, even after a very long search I could not find any semeai for which my Second Throw-in would result in a disadvantage for Black. Please note that my Second Throw-in must be played just now, as Black's group at the right edge lost a decisive liberty at as a result of the first throw-in at . If Black continued with , White would connect at in sente, threatening to capture Black's hanezeki group below. Black would have to take White's group a liberty with , reverting to Fujisawa Hideyuki's original line of play. Before this exchange in the right centre, however, the upper kikashi in the hanezeki , would have to be inserted, as found by Cheng in his 1988 book (see below). | |
: | |
: : It threatened Black's atari at , which White would be unable to connect with successfully, due to . Alternatively, White could also fill her lower false eye with . | |
Years later in China ... | |
: This was not particularly surprising, because our collected findings as of June 2008, which we had handed over to the head of the Chinese Professional Go Organisation with a polite - but unanswered - request for qualitative feedback, had quite obviously been passed on to him. | |
Let's return to the amateur era, enter the amateur analysis room, and stay there for a while ... | |
In essence, Fujisawa Hideyuki's reasoning means that Black would have to swear off the loss of a shared liberty with White's group in the (temporary) seki below. The loss of one liberty is relevant only in the Capture Variation, as Black's large group will be taken off the board in the Semeai Variation anyway. In the course of the resolution of the hanezeki in the Capture Variation, White's group will be taken off the board. | |
Only afterwards can Black deal with eliminating the next group. The all-deciding question is: Can Black succeed with the Punishment Semeai and prevent his group from being taken off the board?? | |
In order to compare the various scenarios, we will determine how many moves Black needs for occupying the "outside" liberties of White's upper group in the hanezeki until it is in atari. We will see below that the shared liberties above White's group do not really matter in this context. | |
, : The need to play the upper kikashi at "early" was discovered by Cheng in 1988, but exists in the classical solution only. For further details, please refer to section "Kikashi in the Hanezeki" ( 2027) In contrast, the lower kikashi with the atari at is not mandatory even in the classical line of play and could be waived until the end. | |
Capture Variation: Black needs one move to give atari at White's group. | |
Let's go back in time again and look over Fujisawa Hideyuki's shoulder ... | |
This is the comparable position in the Fujisawa Hideyuki's line of play, after Black's forcing exchange , . | |
Capture Variation: Black needs two moves to give atari at White's group. | |
Half a decade later in China ... | |
: Black is forced to occupy a shared liberty with , in order to prevent his group below from becoming captured. Please note that White will not play the second forcing exchange , before her decision point, as it would lose points in the Capture Variation unnecessarily. Black's stones and will provide White with an additional benefit of four points in the Semeai Variation. Please remember that at that time - before Cheng's improvements - the Semeai Variation was more favourable for Black than the Capture Variation. | |
Capture Variation: Black needs two moves to give atari at White's group, as many as in Fujisawa Hideyuki's line of play. | |
VAR | |
Black must reduce White's additional gain mentioned above by inserting the upper kikashi in the (temporary) seki as early as possible. This exchange is Black's priviledge, also explained by Cheng in his 1988 book. | |
Capture Variation: Black needs two moves to give atari at White's group, so nothing has changed with regard to the relationship of liberties for the Capture Variation. | |
///: Semeai Variation: The exchange of for remains White's priviledge, which will be played in the Semeai Variation only. Black's upper kikashi in the hanezeki reduced White's additional territorial gain through Cheng's improvement by two points. The Semeai Variation will end with Black + 2 now, the same score as for the classical Capture Variation. | |
Let's return to the amateur analysis room, and compare the world of professionals with that of amateurs ... | |
Black's territory in the Capture Variation: Left - Cheng's line of play:
= 33 points in total Right - After my Second Throw-in
= 34 points in total Black gained one point by my Second Throw-in, compared to the correct classical solution. | |
White's territory in the Semeai Variation: Left - Cheng's line of play:
= 38 points in total Right - After my Second Throw-in
= 36 points in total White lost two points by my Second Throw-in, compared to the correct classical solution. | |
Liberties in the Capture Variation: With Second Throw-in (at right), Black needs only one move to put White's upper group in the hanezeki in atari, one move less than with the correct classical solution (at left). However, this seemingly advantage for Black is irrelevant, as Black's large group in the upper right has one more liberty in the classical line of play, so both effects compensate for each other. Thus, it will remain a mystery what made Fujisawa Hideyuki reject the Second Throw-in. | |
Let's make a short detour to the dawn of time ... | |
Referring to Fujisawa Hideyuki's choice , for starting the endgame at the left side, which was analysed in detail in the previous section, ... | |
... let's try to find out what KataGo thinks about the topic discussed above ... | |
: Please note that KataGo will have exchanged for in the temporary seki much earlier in the game. | |
: (100 2026) Playing Fujisawa Hideyuki's classical push with , instead, would be a one-point mistake. : : Continuing with the "usual" attachment at would be mistaken here. Should Black have played Harry's Hasami-Tsuke Sequence earlier (then with instead of ), White would have to exchange the peep for Black's connection before she occupied the Guzumi Point with . Please note that the reduction of White's upper right corner territory ends in sente for Black, which - according to KataGo - seems to be worth one point overall, compared to Fujisawa Hideyuki's classical sequence. | |
: : We manually enforced Fujisawa Hideyuki's Atari . | |
: : : : | |
: : : : : : | |
Black must not play any reduction. | |
Capture Variation: Compared to Our Solution (2015 / 2017), ...
In total, Black lost six points. Black + 5 => White + 1 This is one point better for Black than without my Second Throw-in, as expected. | |
Semeai Variation: Compared to Our Solution (2015 / 2017), ...
In total, Black gained one point. Black + 3 => Black + 4 | |
VAR | |
: ( 2026) We inserted this move manually. | |
: | |
: As a matter of course, KataGo favoured the continuation with Yamada Shinji's Tsuke in the upper left corner. : : : : | |
: : Playing the atari of at the upper edge or cutting at in the Guzumi Area (quite also considered by KataGo), instead, would not affect the outcome of the game. White's previous move was played outside the Main Semeai Area, so Black gained one tempo in the Main Semeai. | |
: : : : Please note that Black is par with the Punishment Semeai Liberty Level again, so he will not get any opportunity to exploit White's remaining weakness here. : : | |
Black plays 1/1 reduction. | |
Capture Variation: Compared to the superordinate variation, ...
In total, Black lost one point. White + 1=> White + 2 This is the same overall effect as without my Second Throw-in. | |
Semeai Variation: Compared to the superordinate variation, ...
In total, Black lost three points. Black + 4 => Black + 1 | |