#4 FBR "holding" rule ambiguity (Twilight-Chess)

[Trevor Davis]

According to the FBR documentation, "holding" means that captured pieces are added to the holding area and can be dropped. This could imply that in Twilight-Chess one could drop both pieces that "warped" to the holding area as well as any captured pieces.

One could add a new "holding" attribute called something like "pocket" to modify the default behavior of "holding" such that captured pieces are NOT added to the holding area (only pieces initially there or that warped there can be dropped). Or maybe only "warp" and "drop" need to be specified if captured pieces will never go to holding i.e. "warp" implies a holding area that accepts the warping pieces but not necessarily captured pieces. This would be like the "Pocket-Knight Chess" variant which doesn't specify "holding" at all even though it has exactly one pocket piece in holding that can drop (or should it also specify holding?). Then Twilight-Chess would have FBR rules:

royal castling=960 holding=pocket warp drop=P,[2-7]

or maybe

royal castling=960 warp drop=P,[2-7]

p.s. Combined with the board size the notation for initially placing pieces in the holding zone is unambiguous for Pocket-Knight but maybe a little confusing (some might think it is an incorrectly specified 9th row). A different delimiter might separate the initial pocket Knights more clearly i.e. rrnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR|Nn .

[Gregor Cramer]

You're right, this is still a lack in clear definitions. I like the idea to have the attribute "pocket" for rule "holding", this seems to be the most flexible solution.

So the FBR rules will be re-defined according to your suggestion:

Twilight-Chess: royal castling=960 holding=pocket warp drop=P,[2-7]
Pocket-Knight: royal castling=960 holding=pocket drop=N

A different delimiter might separate the initial pocket Knights more clearly i.e. rrnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR|Nn

I agree, it would be better to use a different delimiter, but I will not extend the syntax for pieces in holding. See BPGN - Bughouse Portable Game Notation, here the delimiter "/" will be used. This standard exsists since a longer time, so I have adopted this. (And in BPGN "|" will be used as a delimiter for the boards.)