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WandererXII / lishogi

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Chu shogi doublecaptutre pawn/gb and lion #817

Open olekawaii opened 8 months ago

olekawaii commented 8 months ago

In this position https://lishogi.org/editor/chushogi/12/12/12/12/6n5/6i5/5N6/12/12/12/12/kK10_b_-_1 doublecapturing the gb and lion is illegal but we think it should be legal. After capturing the gb, the lion is no longer defended so there's no reason it shouldn't be capturable. One could argue that the gamestate doesn't change mid move but this isn't true. In this position https://lishogi.org/editor/chushogi/12/12/12/12/5n6/6i5/5N6/8b3/12/12/12/kK10_b_-_1 the lion is undefended but can't be doublecaptured because after taking the gb, the gamestate changes and the lion becomes defended by the bishop. These examples are inverses and they should follow the same rule. https://media.discordapp.net/attachments/1129416204335984680/1221922231249145876/lionr5.png?ex=670d8242&is=670c30c2&hm=47eb20f95d82d0bb5c188785b0c353aeaf39c34809c1cf44ecd0b718877e0306&=&format=webp&quality=lossless&width=2520&height=664

WandererXII commented 8 months ago

If I'm not mistaken I believe CSRM rules disallow it tho, this was mentioned in the testing page: https://lishogi1.org/assets/sandbox/chushogi/index.html?v=3#21 I do agree that your interpretation is more consistent, but I tried following the CSRM rules... Although sometimes I don't really like them.

daxx00 commented 8 months ago

Of all the renmei rules pertinent to actual gameplay, this is the one with most general opposition and the most likely to have an impact. Prohibiting the capture here serves no purpose. The renmei cites their only reason for this prohibition as being the lion is defended before the whole move, but the consideration of game states only after every whole move is merely a convention brought about by the fact that most games don't have multi-step moves, and not anything defined by rules. None of the historical mating problems hint to such a prohibition.

PraseodymiumSpike commented 8 months ago

We should follow the current Chu Shogi Renmei rules in my opinion.

amdewitt commented 6 months ago

Perhaps we can include parameters that select a ruleset? For example, historic rules vs Chushogi Renmei rules? Of course, I'd prefer that we follow the historic ruleset over the Chushogi Renmei rules any day. If it isn't broken, don't fix it.