I ask for permission to copy glaurung code to support UCI.

[Anonymous]

Jos? Carlos:
>Yes, distance to conversion sounds like a good idea.
>But I think it also has flaws: after the conversion, the position might be
>a mate in 51, so it should be considered draw, also before the
>conversion.

Correct. Uri said how to do it.

>Maybe all of this is solvable or very rare to be important...

I think it is solvable, and even not that hard.

When you and Uri used "conversion", it has to include pawn moves, too. Sometimes, this is called DTZ - distance to zeroing move, because conversion and pawn moves zero the 50 moves counter. As a byproduct, this yielded in an idea, that even saves lots of recources compared to the Nalimov generator, that was available some time ago at Hyatt's site. You can consider all pawn positions as different TBs. Instead of KPK you start with KP(h7)K, and work backwards until KP(a2)K and consider it as 48 different TBs. (In reality, one might only have 24 different ones here, and it is also a bit tricky to code, because of all the symmetry, that is used). Instead of needing the whole TB in RAM somehow for efficient generation, one "pawn slice" will be enough now. Of course it won't matter for KPK, but for the larger ones.

Cheers,
Dieter

[José Carlos]

When you and Uri used "conversion", it has to include pawn moves, too. Sometimes, this is called DTZ - distance to zeroing move, because conversion and pawn moves zero the 50 moves counter. As a byproduct, this yielded in an idea, that even saves lots of recources compared to the Nalimov generator, that was available some time ago at Hyatt's site. You can consider all pawn positions as different TBs. Instead of KPK you start with KP(h7)K, and work backwards until KP(a2)K and consider it as 48 different TBs. (In reality, one might only have 24 different ones here, and it is also a bit tricky to code, because of all the symmetry, that is used). Instead of needing the whole TB in RAM somehow for efficient generation, one "pawn slice" will be enough now. Of course it won't matter for KPK, but for the larger ones.

Cheers,
Dieter

Hi Dieter,
Yes, exactly, conversion in this context includes pawn moves. The whole idea makes a lot of sense.
But I wonder if chess rules should be changed to allow longer mates. The 50 moves rules was introduces, I guess, to prevent eternal games, but on the other hand, there's a rule such that if you announce mate in n, and you can prove it, of doesn't matter if your flag falls, you win. I think this rule should be extended to mates beyond the 50 moves rule, as they can be "proven" with computer assistance.
I vaguely recall a discussion about this in CCC long time ago, but now adays, computer find longer mates and they are correct beyond all doubt.
Should FIDE not accept the proposal, maybe computer chess tournaments could implement this rule independely.

[Uri Blass]

Hi Jose,

You say:

"there's a rule such that if you announce mate in n, and you can prove it, of doesn't matter if your flag falls, you win."

I do not know about that rule.

If your flag fall the only case that you win is when the board position is mate at the time that the flag falls.

Uri

[José Carlos]

Hi Jose,

You say:

"there's a rule such that if you announce mate in n, and you can prove it, of doesn't matter if your flag falls, you win."

I do not know about that rule.

If your flag fall the only case that you win is when the board position is mate at the time that the flag falls.

Uri

I don't know if the rule has changed lately. I was an active player until 2000 or so, and when I played in tournaments, you could call the arbiter, claim "mate in three" and let the flag fall. I had read that rule in the chess laws (I had an old book in spanish with the chess laws, written by MC Burdio, I'll look for it and search for the rule number), and I also had it happen in a Murcia ch. in the board just at my left. White had flag about to fall, he was checking the opponent like crazy. At some point, he called the arbiter and claimed mate in x (I don't recall the x) and the flag fell. The arbiter asked the player to prove it. The point was awarded.

[Uri Blass]

Hi Jose,

You say:

"there's a rule such that if you announce mate in n, and you can prove it, of doesn't matter if your flag falls, you win."

I do not know about that rule.

If your flag fall the only case that you win is when the board position is mate at the time that the flag falls.

Uri

I don't know if the rule has changed lately. I was an active player until 2000 or so, and when I played in tournaments, you could call the arbiter, claim "mate in three" and let the flag fall. I had read that rule in the chess laws (I had an old book in spanish with the chess laws, written by MC Burdio, I'll look for it and search for the rule number), and I also had it happen in a Murcia ch. in the board just at my left. White had flag about to fall, he was checking the opponent like crazy. At some point, he called the arbiter and claimed mate in x (I don't recall the x) and the flag fell. The arbiter asked the player to prove it. The point was awarded.

I also played chess before 2000 and I never remember that rule.

I remember a game when with KBB vs K I gave a mate at the same move that my flag fell and it was a win but the position in the board was mate in the time that my flag fell and nobody told me that I could stop the clock and claim mate before it based on forced mate.

Uri

[Uri Blass]

I can add that other players in the israeli chess forum also say that there is no possibility to claim win based on forced mate if there is no mate in the board.

Uri

[José Carlos]

I can add that other players in the israeli chess forum also say that there is no possibility to claim win based on forced mate if there is no mate in the board.

Uri

Ok, I'm looking for that book.
If my memory is wrong again... well, might have a serious problem (not joking this time)

[Sven Schüle]

Hi Jose,

You say:

"there's a rule such that if you announce mate in n, and you can prove it, of doesn't matter if your flag falls, you win."

I do not know about that rule.

If your flag fall the only case that you win is when the board position is mate at the time that the flag falls.

Uri

Hi Jose, hi Uri,

as an active chess player and also arbiter (although without license) I can tell you that there is no such FIDE chess rule. The game is won if you mate the opponent before your flag falls, if your opponent resigns, or if your opponent's flag falls and you have sufficient mating material. But you can't win a game by proving that it's a forced mate in N.

If this has been practiced somewhere then different rules have been applied (this might be possible of course).

Cheers,
Sven