FEN 10x10 Checkers position

[Ron van Bemmelen]

L.S.,

I am working on implementing the Winboard protocol in my java-based Draughts program. (Draughts a.k.a. 10x10 checkers). For testing I am using Winboard Alien 4.5 with the Nebiyu Draughts engine. I would like to set-up a tournament with a File with Starting Positions. For some reason some FEN's are not accepted. For example:

the position after white d3e4 and black i6j5
[FEN "1p1p1p1p1p/p1p1p1p1p1/1p1p1p1p1p/p1p1p1p3/9p/4P5/1P3P1P1P/P1P1P1P1P1/1P1P1P1P1P/P1P1P1P1P1 w - - 0 2"]

{--------------
. p . p . p . p . p
p . p . p . p . p .
. p . p . p . p . p
p . p . p . p . . .
. . . . . . . . . p
. . . . P . . . . .
. P . . . P . P . P
P . P . P . P . P .
. P . P . P . P . P
P . P . P . P . P .
white to play
--------------}

Most likely the "9p" fragment is not FEN-compliant. How to define an acceptable FEN for draughts ?

Thanks,
Ron.

[H.G.Muller]

What exactly is not accepting the position? WinBoard Alien or NebiyuCheckers?

Was WinBoard already switched to 10x10 before you tried to load the FEN? When I start it as 10x10 checkers, (-boardHeight 10 -boardWidth 10 -variant checkers) and paste in your FEN in game-viewer mode, WinBoard Alien accepts it without complaint.

[Ron van Bemmelen]

Thanks for the swift reply.

These are the steps I have taken to set-up a tournament with a File with Start Positions:
OS = Windows 8.1
double click "WB-alien"
WinBoard StartUp dialog
choose (default) play against a chess engine or match two engines
choose Specify Chess Engines:
- "Nebiyu Draughts" ...
- "Nebiyu Draughts" ...
OK
WinBoard: NebiyuCheckers_1.41 dialog, shows 10x10 board
Choose menu Options > Tournament...
Tournament file = test (non-existing file)
Tourney participants
- Nebiyu Draughts
- Nebiyu Draughts
File with Start Positions
- StartPosition.fen
OK

This results into an error message being displayed: Illegal move "b3c4" from first machine, the board is being reset to 8x8 and shows an illegal draughts position.

The StartPosition.fen file contains only:
[FEN "1p1p1p1p1p/p1p1p1p1p1/1p1p1p1p1p/p1p1p1p3/9p/4P5/1P3P1P1P/P1P1P1P1P1/1P1P1P1P1P/P1P1P1P1P1 w - - 0 2"]

Where am i missing the point ?

Thanks,
Ron.

[H.G.Muller]

A .fen file should only contain bare FENs. What you print here is the FEN tag of a PGN game, which contains surrounding stuff (brackets, the FEN keyword, quotes). WinBoard would certainly choke on that when it expects a FEN. Try the line

1p1p1p1p1p/p1p1p1p1p1/1p1p1p1p1p/p1p1p1p3/9p/4P5/1P3P1P1P/P1P1P1P1P1/1P1P1P1P1P/P1P1P1P1P1 w - - 0 2

in the .fen file stead. For me this worked in a simple two-players match (select NebiyuCheckers in the Startup Dialog for first and second engine, with Additional options -boardWidth 10 -boardHeight 10 -variant checkers (or with those options on the engine lines), select the FEN file as position file in the Tournament Options dialog (no participants or tourney file) and select Machine Match from the Mode menu.

The other format would be understood in a game file (.pgn), but it probably would need extra PGN tags (like a variant tag) to be fully understood. Starting from a PGN file is only useful if you want all games to start from the standard opening position, and force some moves into them from there.

[Ron van Bemmelen]

Works fine now.

Thanks for the help.