BrainKing - Diskussionsforum (Chess variants (10x8))

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Chess variants (10x8)

Sam has closed his piano and gone to bed ... now we can talk about the real stuff of life ... love, liberty and games such as
Janus, Capablanca Random, Embassy Chess & the odd mention of other 10x8 variants is welcome too

For posting:
- invitations to games (you can also use the New Game menu or for particular games: Janus; Capablanca Random; or Embassy)
- information about upcoming tournaments
- disussion of games (please limit this to completed games or discussion on how a game has arrived at a certain position
... speculation on who has an advantage or the benefits of potential moves is not permitted while that particular game is in progress)
- links to interesting related sites (non-promotional)

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15. april 2003, 19:34:26

Grim Reaper

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Ämne: Bishop + Knight Database

I found the bug in my database code. It was very stupid, of course. But hopefully you will be able to understand my logic flaw. Ok, the endgame is Bishop + Knight versus King. You are on the strong side, and you know you have a mate in 1 move. So I was generating every Bishop move from the position, then testing to see if the enemy King was checkmated. I was also generating every Knight move from the position to see if the enemy King was checkmated.

There, now do you see my logic flaw?

It is subtle. And it is NOT related to the Knight not being able to force checkmate. There are certainly mate-in-1 positions where the Knight seals the win due to an opponent's misplay.

I WAS NOT GENERATING KING MOVES LOOKING FOR MATES IN 1!

It never occured to me that the King could move in such a way to reveal the Bishop and exhaust a flight square for the enemy King, so my mate in 1 list was incomplete. This effects everything else in the database.

Now that it has been indentified, I will recompute the database, then regrade everybody's longest win.

--Ed

15. april 2003, 21:00:49

Fernando

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Ämne: Re: Bishop + Knight Database

Ed, how does looking for King moves or not looking for King moves affect the whole database? Does the program have to consider where the King can move when a Bishop or Knight move will effect checkmate? And how do I enter your "contest"? I was reading the postings, and just found out.