En passant : who is guilty ?

[Olivier Deville]

In a game between Tristram and Zotron that was just played, after Zotron played b7-b5, Tristram wanted to take en passant with a5xb6, which was a legal move.

Tristram sent the following move :

839500<1:move axb6 ep

There was no reaction from Arena and Tristram lost on time.

Who is guilty ? Tristram for sending its move in non-standard format, or Arena for not transmitting this move to the opponent ?

Olivier

[Richard Pijl]

From the Winboard Standard:

Your engine is making the move MOVE. Do not echo moves from xboard with this command; send only new moves made by the engine.

For the actual move text from your chess engine (in place of MOVE above), your move should be either

* in coordinate notation (e.g., e2e4, e7e8q) with castling indicated by the King's two-square move (e.g., e1g1), or
* in Standard Algebraic Notation (SAN) as defined in the Portable Game Notation standard (e.g, e4, Nf3, O-O, cxb5, Nxe4, e8=Q), with the extension piece@square (e.g., P@f7) to handle piece placement in bughouse and crazyhouse.

xboard itself also accepts some variants of SAN, but for compatibility with non-xboard interfaces, it is best not to rely on this behavior.



From the PGN standard:

En passant captures do not have any special notation; they are formed as if the captured pawn were on the capturing pawn's destination square.

[Olivier Deville]

Thanks Richard !

So it seems that Tristram is culprit for adding the unnecessary "ep" mention to the move.

Olivier