Sometimes I see White R18 here. I’m pretty sure it’s a mistake, but I’m not sure whether it receives enough play to be called Common Mistake.
Has anyone else seen R18 much here? Or against the Shusaku kosumi?
As I understand it, R18 is only really a move when Black has played some kind of pincer, as well as having this supportive stone on the board.
I think R18 is not a huge mistake, but it seems too slow to play in the early game, when the upper side and right side are still open.
I don’t think I’ve seen R18 much, but I can image that some 10k-5k players confuse this position with the (formerly) common slide in 4-4 joseki: Play Go at online-go.com! | OGS
I believe bugcat is asking if it should be added as a mistake like this. One of the common complaints of the joseki explorer is not having enough mistakes and refutations. The handful that have been added were from some of the most common joseki in a database of kyu games but not much effort has been put into adding more.
It is hard to be objective for what qualifies as common or a big enough mistake. It is even harder to be objective and thorough in finding refutation lines.
My gut tells me that this is common enough. The other two concerns are tricky though. Is it big enough of a mistake and what is a clear refutation that would make it be useful to be added?
edit: If it was just a simple question about the slide, the only time I’m aware of it is like you said - after a pincer with the Shusaku kosumi. Usually if there is a knight’s move, the 3-3 attach is the shape to contest the corner.
If it was just a simple question about the slide, the only time I’m aware of it is like you said - after a pincer with the Shusaku kosumi. Usually if there is a knight’s move, the 3-3 attach is the shape to contest the corner.
Good point. I can only find a couple of examples for the slide being played against a pincer when Black has made the keima, rather than kosumi:
Iwata–Kitani '59, a game over sixty years old: Iwata Masao (7p) vs. Kitani Minoru (9p) | Waltheri's go pattern search
Zou–Wang '04, much more recent but still not exactly modern: Zou Junjie (5p) vs. Wang Yao (5p) | Waltheri's go pattern search
I can see a few games where that shape happens in the corner, the knights move after the knights move, in the Gogod database.
The only thing is doesn’t seem to be played immediately, it’s much later in the game, lots of tenuki, sometimes different move over.
It might be “common” in a sense as a response to a 3 space low pincer after tenuki, but maybe that isn’t even really a common situation.
Eg Rin Kaiho vs Tozawa Akinobu 4th Ryusei Block D 1994-05-31a.sgf (1.0 KB)
Kind of a low Chinese opening.