Early play on the left side was seen as evidence of home preparation (obviously AI enhanced!) because of the speed of play.
But the most interesting comment was from Ohashi Naruya, a 7-dan pro from the same stable as Nakamura Sumire. He said the triangled last move, rather then the usual press at A, was one that was difficult for a human to play - but was clearly AI induced! Humans are reluctant to play the hazama shape this creates. Maybe that reluctance explains why this shape is sometimes called an elephant jump. Sensible elephants can't jump. Sensible players can't make an ungainly hazama shape. The weakness at B (the elephant's eye) is just too debilitating.
Of course we already know that there are special occasions when the hazama is, if not necessarily good, at least interesting - a sort of sacrifice tactic to get the opponent to play on the eye and get rolled on by Nellie on at least one side.
However, the AI use of hazama seems somewhat different from that and it would further seem that Shibano may have worked out why. Or at least is confident of now testing his lab research in the field.
And maybe Iyama has seen the same light? His next move was at C. This hazama is an old joseki ploy, of course, but I'm guessing strongly that Iyama played it less out of respect for old joseki books and much more because of its overtones of AI strategy.
If you wonder what these are, I can offer another scrap or two by quoting from my own Go Wisdom entry on "Direction of Play":
In the early fuseki, as distinct from fighting, the hazama may not actually change the direction, but it does seem to offer a better choice of future directions than many other moves... Sometimes, during fighting, you wish to change direction. There are good and bad ways to do this. The good ways include mainly these tactical manoeuvres: cut, nobi, tsuke, cap, inducing moves (→ momentum), hazama, hasamitsuke, sabaki and peeps.
