What do we teach a DDK about this move?
$$Bc DDK move
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$$ | . . . O . X . . 9 a . . . . . X . . . |
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$$ | . . . O . . . . . . . . . . . . . . . |
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- Click Here To Show Diagram Code
[go]$$Bc DDK move
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$$ ---------------------------------------[/go]
15 block LZ with some number of rollouts says that this loses 1.5% to par. As it turns out, there is a recent pro game with the plays up to this point, Tuo Jiaxi, 9 dan (W) vs. Lian Xiao, 9 dan, 2018-08-06, which is in the Elf commentaries. This extension did not show up in the commentaries, getting fewer than 1500 rollouts, so I don't know what winrate estimate it got. The extension to
a got 5.2k rollouts, for a loss of 1.3%. (Elf gives larger differences than LZ, so maybe LZ gives it something like a loss of only 1%.) Should we tell the DDK why the extension to
a is better? Of course. It is established go knowledge and generalizes to other situations.
But Lian Xiao played

in the next diagram, and Elf agrees, with 26.7k rollouts. I also agree.
$$Bc Elf's top choice
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$$ | . . . O . . . . . . . . . . . . . . . |
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$$ | . . 9 . . . . . . . . . . . . . . . . |
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$$ | . . b . . . . . . . . . . . . . . . . |
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$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Bc Elf's top choice
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$$ | . . 9 . . . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
Elf also likes
b, with a "loss" of 0.1% and 11.9k rollouts. Should we teach the DDK those moves, as well? I say yes. Go is not for the faint of heart.
But is
a playable? Well, Elf prefers the other plays, but not by enough to say that
a is a mistake. And in another game vs. Tuo, 2018-05-14, Zhao Chenyu, 6 dan, played that very extension.
