John, I think this is (another!) case where you, with your broader and deeper knowledge of non-English Go sources (Kitani's dictionary is 1930s?) have a wider view than what I would characterise as the "standard western Go theory" which is mostly based on Ishi press translated Japanese books from the 70s like Ishida's joseki dictionary, the Elementary Go series, Go World and then later recycled through Sensei's Library.John Fairbairn wrote: I haven't checked all joseki dictionaries, but I don't think AI is teaching the human pros anything here. Kitani says 'a' is the joseki move. 'b' is not labelled a joseki but is commonly used when you want to emphasise Black's low position. He also says 'b' is not a move you would necessarily want to pay at once.
He seems sniffy about the various kakaris (they strengthen Black too easily) but if one is needed he seems to prefer to the two two-space third-line kakaris (i.e. high and low), and of course in that case White is at least controlling the direction of play.
Checking Ishida's joseki dictionary volume 3 (1977) it has only 2 chapters on the 3-3 points and the first is about the shoulder hit, and second the 2 space high approach, with intro;
After showing the crawl and slide (with comment that shoulder hitter can jump rather than extend) the very first diagram is:The shoulder-hit has traditionally been regarded as the only move in answer to the 3-3 move. It is certainly a powerful move which takes advantage of the lowness of the 3-3 stones, but recently there has been a gradual shift in opinion.
Dia 2 then shows black 2 attaching to left of 1 and taking top side and letting white turn, and Dia 3 isDia 1. (the basic pattern) White continues by jumping to 1 or blocking at 'a' or playing elsewhere. White 1 is the most common. Up to 3 is the basic pattern. Black can also play elsewhere instead of 2. If white omits 3, 'b' is a good point for Black.
So the centre jumps of Dia 1 are claimed as normal and most common, with the turn slightly inferior but not worth worrying about. This judgement is different to my pre-AI knowledge (from Matthew Macfadyen) that the shoulder hit and jumps joseki is bad for white, and AI agrees, and also agrees the turn is better, not a slightly worse compromise.Dia 3 (simple). Blocking at 1 is the most straightforward move. The sequence to 3 entails a slight compromise on White's part, but not to a degree worth worrying about. This result is equal. Playing at 2 can be regarded as absolutely necessary.
So had things changed from Kitani's time with the shoulder hit growing in favour, and then starting to wane by the 70s, or is Ishida misrepresenting a wider variety of thought prevalent in Japan in the 70s? Or was Kitani's thinking back then unusual among standard pro thinking?
Takao Shinji's joseki dictionary from 2012 also leads with the shoulder hit and jumps as the main variation, so the "gradual shift in opinion" mentioned in Ishida doesn't seem to have lasted long enough to make Takao say something different. (Or did John Power just rehash Ishida's dictionary and Takao didn't have much input of new thinking
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