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Blue Chip Chess. A chip, moved each turn by the players, denotes a square where pieces may not go to. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2023-01-16 UTC

I now also succeeded in making the Interactive Diagram's AI play Blue Chip Chess. This was quite a bit harder than Refusal Chess, because of the obligation to move the Chip, and consequently the possibility to 'reserve' the target square of your best continuation move. This rule causes each FIDE position to have two scores: one for when you can place the Chip where it maximally hinders the opponent, the other for when you cannot do that, because the Chip is already there. So you cannot unconditionally ignore the best move in every position (like in Refusal Chess), and not even only ignore it when it is a non-capture (as captures cannot be hindered by the Chip). In any position you can be hindered by two Chip placements: when the Chip is blocking your own best FIDE move, or when the Chip is preventing your best Chip placement because the opponent already put it there. The search will have to figure out which of the two would be better, as well as which move is best. (Which can be a different move for each of the Chip placements.)

This all appears to work now. E.g. setting up a mate threat by Rh8-a6, Ng8-b6, Bc8-b5, h7-f6, d2-d6, f2-f6, Rh1-b3 (threatening 1. Rh3 ... 2. Rh8#), and playing a useless move 1... Ra5, Chip to a4, the AI (at 3.5 ply or more) indeed plays Rh3, and reserves Rh8# by placing the Chip on h8. (Of course black could have staved off the mate by playing the Chip to h3, keeping the Rook from the h-file. This would not work forever, though, because white can then play Rg4, Chip h4 to reserve his access to the h-file. So it would be better if black starts ply placing the Chip on h8 himself. This time not to reserve a FIDE move, but reserve the Chip placement he will need on his next turn. He can keep that up forever.)

You might have to append the URL with ?nocache=true to see the modified page rather than the version cached by CloudFlare. (Or click this link.)

Peter Aronson wrote on 2003-01-18 UTCExcellent ★★★★★
Nice idea! With only a small change, this has a big effect, but the result is still Chess.

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