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Old August 29th 17, 10:07 AM posted to,
Martin Brown[_2_] Martin Brown[_2_] is offline
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First recorded activity by ChessBanter: Jul 2017
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Default Engine puzzle position

On 27/08/2017 05:31, Marc Moisan wrote:
On 2017-07-22 04:46, Rainer wrote:

NB: there is a decades-old controversy whether it's ok to return a draw
score after the first position repetition, or if this should be done
only after the second repetition. One can argue either way, I'll let
that aside.

The relevant rule in the FIDE laws of chess is 9.2, which reads:

The game is drawn, upon a correct claim by the player having the
move, when the same position, for at least the third time (not
necessarily by sequential repetition of moves)

a. is about to appear, if he first writes his move on his
scoresheet and declares to the arbiter his intention to make this move, or

b. has just appeared, and the player claiming the draw has the move.

In other words the position ought to occur (about to or just did) for
the third time, but in addition must also be so claimed by the player
having the move. It is not an automatic draw (although most programs
make it an automatic draw).

We know what the FIDE rules are. The problem here is that for reasons of
computational convenience these engines return a draw as the evaluation
on the first repetition of a position even when it is clearly lost.
Worse it makes the same mistake when analysing/annotating a played game.

I can see why it might cut some corners in game play.

I have also noticed that the UI for Deep Fritz 14 makes a considerable
number of errors in distance to mate calculations during blunder checks
that were correct in earlier versions of the software.

Martin Brown