Variations of Our Solution (IIIa)
No Early Kikashi
Main Line
We start our analysis from a position, where Black has not played any of his kikashi , / , in the hanezeki at the right and , / , at the left side. Please note that Black has eight Main Semeai Liberties in the moment, and so is one over par with regard to the Punishment Semeai Liberty Level. | |
: : (A 648ab; B 648gf; C 649aa) White cannot take advantage if Black does without this kikashi. Black might also continue by immediately capturing White's single stone in the top right, with a move at , or by largely simplifying the issue by KataGo's solid connection at . In both cases, the final scores of the game will remain the same as with this kikashi played "early".
When analysing this position with KataGo (2021i), we found that the atari at White's two stones in the lower left was the top entry in the list of favoured moves. | |
: ( A 648gm; B 648go; C 648gu; D 648hm) Alternatively, Black might push at in the top left, or again play KataGo's solid connection at . Defending his lower left corner with , or blocking with in the left centre, instead, will not change the overall result of the game (i.e. the Capture Variation's score), but Black's score in the Semeai Variation will become worse. | |
: (D 648id; A 648io; C 648ix; B 648kh) White might start her manoeuvre at the left side of the board with the forcing move at in the lower left corner, resulting in a change in the order of moves. Pushing at , or blocking at , instead, are White mistakes. : (A 648ku) Black might consider taking White's group at the left a Main Semeai Liberty by playing at , instead. However, this move will not have the expected result, but lose one point overall. | |
: (A 648kv) We only realized this fact shortly before the 2020 update of our website was completed. We ask for your kind understanding that in this late phase of our elaboration we both felt unable to reduce the move numbers by two in many diagrams, and to restructure the variation tree. However, we thought for long that this atari could be utilised as an additional ko threat. But this is not true, as we only discovered in late 2020. | |
: ( A 648mk; B 648nn; C 648ns) However, heading for Dany's Ko by playing Dany's atekomi , instead, will increase White's score in the Semeai Variation. Erasing Black's potential eye in the centre with the central attachment at , instead, is a White mistake. | |
: (A 648nx) Playing at , instead, will end in a disaster for him : ( B 648nz; C 648oc) Heading for Dany's ko, by playing Dany's atekomi , instead, will increase White's score in the Semeai Variation. Erasing Black's potential eye in the centre with the central attachment at , however, will end worse for her. | |
: ( B 648of; A 648or)
However, this move is not correct, as Black will be pushed below the Punishment Semeai Liberty Level by White's throw-in in the lower left corner.
Joachim found that this is the moment - just after White played her move (=) in the lower left corner - to give atari at White's two stones with a move at , returning to what I thought to be the main line. Black could also survive the Punishment Semeai, if he secured his second eye for his left-hand group by connecting at at the lower edge. But his score in the Semeai Variation would become worse, compared to Joachim's suggestion above. | |
: This move pushes Black below the Punishment Semeai Liberty Level. | |
: Please take notice that I was a bit lazy with the presentation of these two exchanges in many subvariations, where I did not display these four moves explicitly. Simply because I took them for granted, as an integral part of the Main Semeai. : ( A 648ot; B 648ou) White will not connect, but choose Dany's Sacrifice, instead. However, she must be careful with the continuation. We ask for your kind understanding that in the late phase of our elaboration, in which we discovered this error, we felt no longer able to reorganize the variation tree accordingly. | |
: (137 648ov) : (A 648ow) Simply continuing with the Main Semeai, by occupying one of White's liberties at the left, will worsen Black's score in the Semeai Variation only. : (B 648ox) Here, she might also continue with the Main Semeai, instead, e.g. with . | |
: (A 648oy) If Black does without connecting, White will not capture at "early", but wait until after her decision point, so improving her score in the Semeai Variation by two points. | |
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: You will recognise that Black here neither answers White's atari locally, nor pushes at any of the points and . This implies that he is not able to do so; otherwise he would fall prey to the Punishment Semeai. We will illustrate the number of these moves as Black must not play any reduction (which is 0/0 reduction). Please note that connecting at counts twice, as this move costs Black two liberties, not only one (as and ). Black will often not use his potential to full capacity. This will be wise in those cases, where his score in the Capture Variation is better than in the Semeai Variation, and might result in a reduction of the overall result of the game. Any of these moves left unplayed provides White with an advantage of one point in the Capture Variation (i.e. one point of territory), but will cost her one point in the Semeai Variation (i.e. one prisoner). | |
At the end of the previous diagram, it is Black to move. Therefore, we can calculate the relationship of liberties in the Main Semeai. Black needs seven moves at the left to reach White's decision point (she will have to choose between the Capture and the Semeai Variation):
Black's group at the right has 14 liberties left:
This means that Black is ahead by seven liberties, barely enough to not suffer from the Punishment Semeai. | |
We use our 2019 Solution for comparison. Capture Variation:
On the left side of the board, Black gained one point in total. | |
On the right side of the board, White gained two points. | |
In total, White gained one point. White + 1 => White 2 | |
Semeai Variation:
On the left side of the board, Black gained three points in total. | |
On the right side of the board, Black gained two points. | |
In total, Black gained five points. White + 1 => Black + 4 | |