Draw Rules (halfmoveclock,repetition)

[Desperado]

hi everyone,

Just 2 little confusions ...

HALFMOVECLOCK:
===============

when can the player who has the right to move claim draw.

a. halfmoveclock >= 99,100 (doing move 50) ?
b. halfmoveclock >= 101,102 (50 fullmoves done,so claim on move 51) ?

REPETITION:
=========

the claim on 3-time repetition is clear to me, but not so clear is
how to handle the search issues to that rule.
(history positions,treesearch).

(i think, if a repetition doesnt exist in the gamelist(gamelisthistory), the
search profits by interpreting a 2-time repetition as 3-time repetition.
When position already exists(2x) in gamehistory, search should detect the 3time repetition.
I would be interested in your approaches.Influence on transpos-table and
every other experience you have with this issue.)

Michael

[Fguy64]

well, in a real OTB game, if you are the player making the claim, then you must do so before you press your clock. In OTB chess you are within your rights to say "I am about to make this move which creates a 3-fold repetition and claim a draw" stop the clock, and ask for a ruling from the tournament director or arbiter if need be.

not sure if that helps you answer your question though.

as for 50 move, I would say 50 moves by player making the claim, the second player need only have made 49

[Desperado]

...I would say 50 moves by player making the claim, the second player need only have made 49

But you aren t sure (like me), are you ?

(i play chess for more than 15 years now, never used this rule,
never was faced with this _little_ detail. )

[Fguy64]

...I would say 50 moves by player making the claim, the second player need only have made 49

But you aren t sure (like me), are you ?

looks like I was wrong. The claim is made on your time after 50 moves by both players. or if you are the second player about to make your 50th move

so the 2nd player gets first crack at it

http://en.wikipedia.org/wiki/Fifty-move_rule

[Desperado]

super, thx !

then the condition is _ halfmoveclock > 100... _

[Fguy64]

super, thx !

then the condition is _ halfmoveclock > 100... _

no I would say hmc == 100. if hmc > 100 then the second player has missed his initial chance.

depends when the variable is set. even if hmc == 100, if that means the move had already been made, then it is too late for the second player

[Desperado]

both players have to be executed 50 moves.
So the first possibility to claim is on 101(before executing the move 101,
before pressing the clock (before to give up ), because second
player has to be done already move 100 ?!

so i would vote at the moment for hmc>100 !?

Micha

[Fguy64]

both players have to be executed 50 moves.
So the first possibility to claim is on 101(before executing the move 101,
before pressing the clock (before to give up ), because second
player has to be done already move 100 ?!

so i would vote at the moment for hmc>100 !?

Micha

That's not how I see it. The second player can make his claim as he is making his 50th move. In the act of making that move, the HMC flips to 100.

[bob]

well, in a real OTB game, if you are the player making the claim, then you must do so before you press your clock. In OTB chess you are within your rights to say "I am about to make this move which creates a 3-fold repetition and claim a draw" stop the clock, and ask for a ruling from the tournament director or arbiter if need be.

not sure if that helps you answer your question though.

as for 50 move, I would say 50 moves by player making the claim, the second player need only have made 49

It is actually _both_. Both players must have made 50 moves since the last non-capture/non-pawn-push. Once that is satisfied, the side on move can make the claim, or not if he so chooses. But both have to have made 50 reversible moves for a claim to be made.

[xsadar]

super, thx !

then the condition is _ halfmoveclock > 100... _

Actually it's halfmoveclock >= 100, not strictly greater than. The clock starts at zero, so once it reaches 100 either side may claim the draw immediately. And according to the FIDE rules the player making the move to the drawn position (where halfmoveclock == 100) may claim the draw before making the move but stating that they are about to make it. However in computer chess this is done a little differently. With the xboard protocol you should send "offer draw" immediately preceding the move (while clock is at 99), then make the move so that the draw offer becomes a draw claim if playing on ics (if the draw offer is given after the move it is possible for the opponent to move to a non-drawn position before your claim gets processed), then immediately claim the draw with the "result" command. In computer chess you can typically claim or offer a draw regardless of whose turn it is.