Imitating AlphaGo: Self play game 7, continued
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[go]$$Bcm17 AlphaGo 3-3 invasion
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 2 . . . . . . . . . X . . . . . |
$$ | . . 3 O . . . . . , . . . . . X . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . a 4 . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . O . . . . . , . . . O X , X X . |
$$ | . . . . . X . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

is another AlphaGo special, the early, unsupported 3-3 invasion. Why did White block on the top instead of the left, I don't know. AlphaGo imitators may go either way. The keima,

, is AlphaGo's usual choice, unlike humans up till now, who usually hane.

occurs in human play, but "a" was by far the usual choice. Is

superior to "a"? No, we can't say that. For one thing, AlphaGo has played a few more recent games against itself with longer time limits, spending 120 sec./move instead of 45 sec./move, as in this game. In those games AlphaGo has chosen "a". (OC, we cannot conclude that "a" is superior, either.

)
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[go]$$Wcm28
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$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . X O X . . . . . . . . . . . . . . . |
$$ | . 6 X O . . . . . . . . . X . . . . . |
$$ | . 5 X O . . . . . , . . . . . X . . . |
$$ | . 1 X O . . . . . . . . . . . . . . . |
$$ | . X O 2 7 . . . . . . . . . . . O . . |
$$ | . O 3 . . . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . 9 . . . . . . . . . O . . |
$$ | . . . . . a b . . . . . . . . X O . . |
$$ | . . . O . . . . . 8 . . . W X , X X . |
$$ | . . . . . X . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

completes one of the AlphaGo joseki in the top left corner. Note that

makes the ladder work.

Is that why White chose to block on the top side? ¿Quién sabe?
The next two plays are quite ordinary.

stakes out the bottom side, and

plays at the frontier of opposing frameworks, enlarging the White framework while reducing the Black framework. Wa and Wb are also possible, but AlphaGo tends to prefer higher and thinner options.
- Click Here To Show Diagram Code
[go]$$Bcm37 Large framework
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$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . X . X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . X . . . . . |
$$ | . O X O . . . . . , . . . . . X . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X O X O . . . . . . . . . . . O . . |
$$ | . O O . . 7 . . . . . . . . . . . . . |
$$ | . . . . 8 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . a 6 . . , . . . . . O . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . W . . . @ . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . 4 W . . . . . X . . . O X , X X . |
$$ | . . 2 1 . B . . . . . . . . X . . . . |
$$ | . . 3 . 5 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
AlphaGo often plays the attachment,

, with the

and

stones in place. Here the strategy of strengthening the edge of one's framework is well known. With Black strengthened, White can be glad that

is not closer to the Black strength. Also,

works well with

.

is not unusual, but to me it does have that Go Seigen - AlphaGo flavor.

also has an AlphaGo flavor, being a high shoulder blow in preference to other possible reductions.
Note that AlphaGo seems unconcerned that White builds a huge framework. A lot of top pros share such unconcern. FWIW, I would have wanted to play a reduction earlier, such as

at 42 or "a". Maybe that would not have been so good. {shrug} Anyway, if I were trying to imitate AlphaGo I would cultivate that unconcern.
- Click Here To Show Diagram Code
[go]$$Bcm45 Ogeima attack
$$ ---------------------------------------
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . X . X . . . . . . . . . . . . . . . |
$$ | . X X O . . . . . . . . . X . . . . . |
$$ | . O X O . . . . . , . . . . . X . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X O X O . . . . . . . . . . . O . . |
$$ | . O O . . X . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . O . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . 1 2 . . |
$$ | . . . . . . . . . . 5 . . . . 3 a . . |
$$ | . . O . . . O . . . . . . 4 . c O . . |
$$ | . . . . . . . . 7 6 d . . . . X O . . |
$$ | . . O O . . . . . X . . . W X , X X . |
$$ | . . O X . X . . . . . . . . X . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

enlarges the Black framework while reducing the White framework. Note that after

White does not defend at "a" or "b", but jumps to

instead, making use of the aji of

. There is a good lesson in light play there, I think.

White threatens to push through at "c", sooner or later.
Black attacks with the ogeima,

. There is a saying,
Keima for attack. Characteristically, AlphaGo plays one point higher and one point thinner.

is, I suppose, the choice of a plurality of pros.
Attachment for sabaki. Amateurs might respond at "d", but again, I think that

is the pro choice. The subsequent fight is quite interesting, but I cannot identify anything peculiar to AlphaGo in it.