Life In 19x19

Black just approached with 1 and then 5 was an interesting move, developing the top side on a more ambitious scale than the more normal one-point jump to a (Elf likes that or e16). If white pushes and cuts then that's taking the bait and black just sacrifices and pushes along the g line to grow a big top, so white doesn't dare to cut yet. 5 makes the press at b a stronger follow-up to keep growing the top. Just making a side extension to c to surround a few points would be slack, white's nozomi at d is nice reduction.

So my first thought was to reduce the top side seeing as black is trying to grow it on a large scale: shoulder hit at k16 would be one idea, or maybe something more gentle like k15 or k14 (which if ignored makes the shoulder hit really easy to play with no worry about a capping play or getting heavy). Then I remembered e which is a nice point to reduce against the upper right shape that I learnt from one of the strong bots on CGOS (either define aka Tianrang or monroe and the other US president bots which were later revealed to be test version of Elf) which often liked to take the corner instead of p18 connect in that bot-favourite attach and hane joseki.

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[go]$$Bc Fan Tingyu (black) vs Shin Minjun
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . 3 . . . . . . . . . . X O O X . |
$$ | . . 4 . . 1 . . . . X . . O X O X X O |
$$ | . . . O . . . c . , . . . . X X O O . |
$$ | . . . . 5 a . . . d . e . . . f . . . |
$$ | . . 2 . . . . . . . . . . . . . X . . |
$$ | . . . b . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . O . . . . . X . . . |
$$ | . . X O . X O . . . . . . O . . . . . |
$$ | . . X X O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Because black exchanged p18 for t17 r15 isn't sente so white has a cut at f, but the right side doesn't look like a scary black potential yet (e.g. q7 shoulder hit) so the r14 stone isn't so important. Rather than cutting it (which black can dodge it would be nice to annoy black's shape and reduce. Here's a dream. In reality black wouldn't 2, 4 is soft, 8 would likely push and cut, so 7 should probably not overplay and be at a or so, but this seems the right sort of idea for white of reducing from the outside.

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[go]$$Wc white dream
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . . . . . . X O O X . |
$$ | . . O . . X . . . 8 X . . O X O X X O |
$$ | . . . O . . . . . 7 . . 4 6 X X O O . |
$$ | . . . . X . . . a . . 3 5 . . 2 . . . |
$$ | . . O . . . . . . . . . . . 1 . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . O . . . . . X . . . |
$$ | . . X O . X O . . . . . . O . . . . . |
$$ | . . X X O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Shin played hane, Fan dodged so Shin took some profit on the right side, and Fan developed the top side even more and got sente. But the profit isn't even that much, black can still cut at a later and then b cut isn't a ladder anymore. Would Cho Chikun the invade/reduce at k16 anyway? With this sequence Elf v1 said Shin went from 63% to 16%.

Click Here To Show Diagram Code

[go]$$Wc Fan Tingyu (black) vs Shin Minjun
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . . . . . . X O O X . |
$$ | . . O . . X . . . . X . . O X O X X O |
$$ | . . . O . . . . . , . . . . X X O O . |
$$ | . . . . X . . . . . . . . 6 . 1 . . . |
$$ | . . O . . . . . . . . . . 4 3 a X . . |
$$ | . . . 0 . . . . . . . . . 8 2 5 9 . . |
$$ | . . . . . . . . . . . . . . 7 b . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . O . . . . . X . . . |
$$ | . . X O . X O . . . . . . O . . . . . |
$$ | . . X X O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Elfv1's intuition on a few playouts: