Please consider the following position: W:W48:B11,12,13,23,32,33,42,43:H0:F1.

In this position, white has two legal moves: 48x37x28 etc. and 48x39x28 etc.. In both cases, the move shows up in the analysis board as 48x6.

My question is: how would one write down the difference between these moves in an OTB game? Maybe instead of 48x6, one would write 48x37x28...x6? Also, whatever the answer is, I think it would be a good idea to implement this on the site as well. Situations like this, where multiple moves have the same notation - although very rare, I imagine - could be very annoying, especially when playing blindfolded.

Good question!

We thought about such notational ambiguities during development, but decided to just show the "48x6", although the server knows the difference internally (as you can tell from the fact that it still sees them as different lines).

Officially (OTB) one is required to write down the entire sequence as you noted. The problem with doing this on lidraughts as well is that one could theoretically created such a large sequence (you should try it with frisian draughts, lots of fun :p) that the move won't fit in the notation window anymore.

Considering that such ambiguities are extremely rare in practice, it seemed like overkill to change the interface to be able to accommodate this.

You do have a point with blindfold chess though, did not think about that one!

Officially do we always write the whole sequence or only in case of ambiguities?

@Finlip usually, you don't write the whole sequence, only the ending square/ starting square.

Thank you for the fast answer @RoepStoep. It's good to hear the issue has been considered and doesn't cause any problems internally. That being said, the current solution still doesn't seem perfect, because a notation is supposed to be unique for a move. A possible fix might be to only include a square which is unique for the capture sequence. For instance, in the position I gave, one of the legal moves would shows up as "48x37x6". A possible issue with this idea is that there might be times where you would have to show more than three squares to differentiate between two similar moves, but I think such positions are much rarer than positions where three squares is enough.

I also came across abbreviated notation. I think that's pretty cool.

I also came across this, which is another way of solving it.

pdn.fmjd.org/pdnnext.html#alternative-move-disambiguation

For the UI problem, you can also make use of this. You just show the regular notation always, but if a capture is ambiguous you show the full capture sequence if the player hovers over the notation with his/her mouse.