vchess.club : play chess variants

Hello ! Happy new year everyone ^^

@opperwezen : interesting variant, I'll add recycle chess as soon as I finish refactoring some code. Glad that you enjoy checkered chess :)

@hyulgaeth : thanks ! Would you like to contribute to the JavaScript code ? It's not java, but not too complicated.

@CrazyHome : I'm not sure about you variant 1, but variant 2 will very likely be added. I thought about it at the beginning but feared that it wouldn't be random enough. But it seems fun. I think it's called Moscow Chess.

@ulath thanks but I'm not so experienced with Javascript yet, when I am I'll investigate :)

I have found a rather strange bug after playing a 30 dark games or something like that over the past weeks: Move 16 from black. I can't do this move and neither have I done it. It rsulted in a double move from white and I have no idea what might be the cause. Good luck.

[Site "vchess.club"]
[Variant "Dark"]
[Date "2019-1-07"]
[White "Computer"]
[Black "Myself"]
[FenStart "nqbrkrnb/pppppppp/8/8/8/8/PPPPPPPP/BNRNKBRQ"]
[Fen "1r2kr1b/4pp2/2pp1Bp1/p6p/4PP2/P5PN/P2PR2P/3RK3 w 0000 -"]
[Result "0-1"]

1.f4 h5 2.Nf2 Nf6 3.g3 d6 4.c4 g6 5.e4 a5 6.Bh3 Bxh3 7.Nxh3 b5 8.cxb5 Qxb5 9.Rd1 Qb6 10.Rg2 c6 11.Re2 Nc7 12.Qg1 Qxg1 13.Nxg1 Nb5 14.Nh3 Rb8 15.Na3 Nxa3 16.bxa3 xa3 17.Bxf6 Bxf6 18.f5 gxf5 19.exf5 Rg8 20.Rxe7 Bxe7 21.g4 hxg4 22.Ke2 gxh3 23.Rf1 Bf6 24.Kd1 Be5 25.Rf4 Bxf4 26.Kc1 Bxh2 27.f6 Be5 28.Kb2 Bxb2

1.f2f4 h7h5 2.d1f2 g8f6 3.g2g3 d7d6 4.c2c4 g7g6 5.e2e4 a7a5 6.f1h3 c8h3 7.f2h3 b7b5 8.c4b5 b8b5 9.c1d1 b5b6 10.g1g2 c7c6 11.g2e2 a8c7 12.h1g1 b6g1 13.h3g1 c7b5 14.g1h3 d8b8 15.b1a3 b5a3 16.b2a3 b2a3 17.a1f6 h8f6 18.f4f5 g6f5 19.e4f5 f8g8 20.e2e7 f6e7 21.g3g4 h5g4 22.e1e2 g4h3 23.d1f1 e7f6 24.e2d1 f6e5 25.f1f4 e5f4 26.d1c1 f4h2 27.f5f6 h2e5 28.c1b2 e5b2

Very strange indeed, I've no clue about this one for now :/ I'll need to re-play the game in Dark mode.

I'm doing a lot of changes to the code, so I won't upload any new versions before a few weeks. For example the "enlightened squares" issue is fixed in the code but not yet on the website. Anyway it's probably not this bug which causes the situation you oberved.

Is there a good way to strenghten the dark bot? It is odd when a queen hits into a pawn that is defended by another pawn, which the bot was able to see. I do not think that would happen in regular 960.

Yes, there are many ways to improve the AI (for several other variants as well). However, this is not the main purpose of the website at least for the moment.

Concerning Dark variant it could be considered to (in random order)
- always cover blind attacking lines on the king,
- remember what is seen at some move and give some probability that the observed piece is still in place N moves after,
- (as you suggest) do not capture something too small when we see an available re-capture
- capture only when enough pieces target the same point (at least 3, maybe 4), starting with the piece of smallest value
- try to cover a maximum amount of squares
- remember the pawn structure to know which squares are safe
- keep pieces defended
...and so on. Maybe in some distant future if my only concern is the bots :)