Check out Symmetric Chess, our featured variant for March, 2024.


[ Help | Earliest Comments | Latest Comments ]
[ List All Subjects of Discussion | Create New Subject of Discussion ]
[ List Earliest Comments Only For Pages | Games | Rated Pages | Rated Games | Subjects of Discussion ]

Single Comment

Interactive diagrams. Diagrams that interactively show piece moves.[All Comments] [Add Comment or Rating]
💡📝H. G. Muller wrote on Thu, Dec 2, 2021 06:45 PM UTC:

I finally got to upgrading the Diagram so that it would be able to support (a limited form of) double locust capture. In particular, I considered it a blemish that it was not able to handle the Lion Dog that occurs in the large Shogi variants (which can make up to 3 radial King steps per turn, and thus capture up to 3 pieces in one move). The AI of the Diagram was already capable of supporting any number of locust captures, but up to now it was not possible for the user to enter a capture with more than one locust victim (in addition to the normal victim in the destination square).

This is now fixed, albeit in a clumsy way. The Diagram still does not support locust capture of any pair of pieces, but only those where these victims are on the same ray, on the first and second square. But that is exactly what the Lion Dog needs. (This limitation came about by the fact that it still uses only a single e.p. square, which then implies the second square.)

There was a lot involved in getting this to work. (It needed new code for generating the move notation, parsing such moves when you paste a game, communicating it to and from the AI, and of course for interpreting the clicks made when you enter a move.) I hope that I got everything right. I also made the Diagram smarter in understanding XBetza descriptors that have both destructive and non-destructive action at the square connecting the legs. (These need a different set of clicks to play: non-destructive intermediates, like the corners in a bent-leaper trajectory, never need to be clicked, while locust victims do.)

The Lion Dog can now be represented in XBetza notation as: KADGHcavKmcafcavKpafcafKcafmpafK . This is a bit cumbersome, but I saw no easy way to allow a 2-out-1-in move (using v in the 3rd leg) only when the first square gets captured or already was empty, and forbid it (using f)when it was an occupied square that was hopped over. So 3 types of three-leg moves need to be described. I guess to also describe null move an extra abK would be needed.

[Edit] I guess that the slightly more compact KADGHcavKmpafcavKcafcmpafK would also work. This only needs two descriptions of the 3-leg move. One for the 3-out move that captures the adjacent victim, and in addition optionally the one on the second square. And another that in any case captures two squares away, and then either continues either out or in. Possibly making a normal capture on its destination. The disadvantage of this is that for the 2-out-1-in move the victims are captured in reverse order (furthest first). Which could make a difference in the case of contageon, when both the captured pieces are contageous. (As they could be in Maka Dai Dai Shogi. Although this is of course a 'never happens' situation.)