PDN long notation disambiguation

[julien007]

PDN 3.0 rules provide (See PDN 3.0 Restrictions)

9.Disambiguated capture sequences have to specify the entire sequence of turning points. A turning point is either the square immediately behind a captured piece, or the square where a turn of direction was made. Leaving out a turning point that is not necessary for the disambiguation is forbidden.

Considering that the software will always blows intermediaries provided they are given a rating removing ambiguities,

Considering further that the complete description of shots is not necessary for formulation of problems and can only spice up their resolution,

Noting that the mention of some or all pieces taken presents decisive advantages relating to the location of the destination square, then only the empty, and the ability to collect pseudo-variants in a single notation to describe in short the true positional variants,

Are this PDN 3.0 requirements the best choice for disambiguation ?

[Wieger Wesselink]

PDN 3.0 rules provide (See PDN 3.0 Restrictions)

9.Disambiguated capture sequences have to specify the entire sequence of turning points. A turning point is either the square immediately behind a captured piece, or the square where a turn of direction was made. Leaving out a turning point that is not necessary for the disambiguation is forbidden.

Considering that the software will always blows intermediaries provided they are given a rating removing ambiguities,

Considering further that the complete description of shots is not necessary for formulation of problems and can only spice up their resolution,

Noting that the mention of some or all pieces taken presents decisive advantages relating to the location of the destination square, then only the empty, and the ability to collect pseudo-variants in a single notation to describe in short the true positional variants,

Are this PDN 3.0 requirements the best choice for disambiguation ?

Hi Julien,

This topic has been discussed during the review, see viewtopic.php?f=53&t=3448&start=30.

Based on that the current choice has been made. Note that the long notation is only required for ambiguous captures. For other captures the short notation can still be used. The current choice has the advantage that no move generator is needed in order to write a PDN viewer. And it is being used in practice, both in game analysis as in software.

Perhaps a different choice would have been possible. But I don't understand exactly what you have in mind for that, nor do I know what pseudo-variants are.

[julien007]

Thanks for your attention.

I understand right that the long notation is only required for ambiguous captures.
I understand too that current choice has the advantage that no move generator is needed in order to write a PDN viewer (however calculations are needed for multiple unambiguous jump).

It's perhaps used both in game analysis as in software, but I never find it use in competition.

I do not find clear rules in this situations. Two recent examples visible on my new page Console pour Dame (*) show that the rules do not seem to be clearly set !

I discover in addition that the proposed rules lead to several possible notation for the same positions. Paste, for example, the following PDN(**) in the right text area of my page, open the console with F12 in Internet Explorer and import the file with the button on the bottom of the text area to note that there is 944 notations for only few ten of different positions.

For example the 32 legal moves (that I call pseudo-variants, they differ only in the notation) which reach the cell n° 6 are in fact only two variants which could be noted 13x30x6 or 13x34x6 ! (I leave it to you to analyse the 640 pseudo-variants and different notations ending in box 13)

I know that this example is a caricature, but it clearly shows the disadvantages of PDN 3.0 rating

My question : What are the recommendations of specialists for the disambiguation in competition ?

Julien de Prabère

(*) A pure HTML and javascript under construction product - See the game 30 Arendo -D'Almeida Championship of France 2012 or 115 Olivan-Farcy of Open International Cannes 2012.


(**) [Event "Quizz"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "Joueur"]
[Black "Joueur"]
[Result "*"]
[SetUp "1"]
[FEN "W:WK13:B7,8,9,10,17,18,19,20,21,30,31,32,33,34,41,42,43,44"]\r\n\r\n*

[julien007]

Complements...

If the problem given by Gérard Taille post as only one solution 1. 3x38, the preceding has effectively 944 «pseudos-solutions» which can be described by :

• 32 «pseudo-variants» to the cell 6, for two variants described by : 13x30x6 (22 cases) or 13x34x6 (10 cases),

• 32 «pseudo-variants» to the cell 11, for two variants described by : 13x30x11 (22 cases) or 13x34x11 (10 cases),

• 640 «pseudo-variants» to the cell 13, for four variants described by : 13x17x30x13 (136 cases) or 13x17x34x13 (56 cases) or 13x21x30x13 (312 cases) (*) or 13x21x34x13 (136 cases).

• 64 «pseudo-variants» to the cell 14, for two variants described by : 13x17x14 (20 cases) or 13x21x14 (44 cases),

• 32 «pseudo-variants» to the cell 16, for two described by : 13x30x16 (22 cases) or 13x34x16 (10 cases),

• 48 «pseudo-variants» to the cell 35, for two variants described by : 13x17x35 (14 cases) or 13x21x35 (34 cases),

• 48 «pseudo-variants» to the cell 40, described by : 13x17x40 (14 cases) or 13x21x40 (34 cases),

• 48 «pseudo-variants» to the cell 45, described by : 13x17x45 (14 cases) or 13x21x45 (34 cases).

(*) Is it not embarrassing to describe a jump with 312 different notations to reach the same position ?

For the sceptics, the 312 PDN 3.0 standard notations for the move 13x21x30x13 which reach the unique position B:WK13:B17,34

Move 13x2x16x27x13x24x38x47x36x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x38x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x47x36x27x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x47x36x27x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x24x38x47x36x27x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x24x38x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x24x35x49x38x47x36x27x38x24x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x24x35x49x38x27x36x47x38x24x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x29x38x47x36x27x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x13x4x15x29x38x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x29x15x4x13x22x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x29x15x4x13x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x29x15x4x13x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x29x15x4x13x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x24x13x22x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x24x13x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x24x13x4x15x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x24x13x4x15x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x24x35x49x38x47x36x27x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x24x35x49x38x47x36x27x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x38x24x35x49x38x47x36x22x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x24x35x49x38x47x36x22x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x38x24x15x4x13x22x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x24x15x4x13x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x24x15x4x13x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x24x15x4x13x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x22x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x22x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x4x15x24x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x4x15x24x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x4x15x29x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x13x4x15x29x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x38x47x36x27x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x38x47x36x27x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x38x47x36x22x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x38x47x36x22x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x15x4x13x22x36x47x38x24x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x15x4x13x27x36x47x38x24x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x15x4x13x24x38x47x36x27x13 remaining piece : 17,34
Move 13x2x16x27x38x49x35x24x15x4x13x24x38x47x36x22x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x27x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x2x16x27x38x47x36x22x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x29x15x4x13x27x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x29x15x4x13x24x35x49x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x13x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x13x4x15x24x35x49x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x35x49x38x27x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x35x49x38x27x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x15x4x13x27x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x24x15x4x13x24x35x49x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x13x27x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x13x27x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x13x4x15x24x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x13x4x15x29x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x38x27x13x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x38x27x13x4x15x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x15x4x13x27x38x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x49x35x24x15x4x13x24x38x27x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x2x16x27x36x47x38x27x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x22x36x47x38x29x15x4x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x22x36x47x38x29x15x4x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x24x13x2x16x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x24x13x4x15x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x24x35x49x38x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x24x35x49x38x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x22x36x47x38x24x15x4x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x22x36x47x38x24x15x4x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x13x2x16x27x38x29x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x13x2x16x27x38x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x13x4x15x24x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x13x4x15x29x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x38x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x38x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x15x4x13x2x16x27x38x24x13 remaining piece : 17,34
Move 13x22x36x47x38x49x35x24x15x4x13x24x38x27x16x2x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x22x36x47x38x27x16x2x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x27x38x29x15x4x13x2x16x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x27x38x29x15x4x13x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x24x13x2x16x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x38x24x13x4x15x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x24x35x49x38x47x36x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x27x38x24x35x49x38x47x36x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x27x38x24x15x4x13x2x16x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x27x38x24x15x4x13x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x49x35x24x13x2x16x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x27x38x49x35x24x13x2x16x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x27x38x49x35x24x13x4x15x24x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x49x35x24x13x4x15x29x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x49x35x24x38x47x36x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x27x38x49x35x24x38x47x36x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x27x38x49x35x24x15x4x13x2x16x27x36x47x38x24x13 remaining piece : 17,34
Move 13x27x38x49x35x24x15x4x13x24x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x27x38x47x36x27x16x2x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x27x36x47x38x29x15x4x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x27x36x47x38x29x15x4x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x24x13x2x16x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x24x13x4x15x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x24x35x49x38x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x24x35x49x38x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x27x36x47x38x24x15x4x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x27x36x47x38x24x15x4x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x13x2x16x27x38x29x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x13x2x16x27x38x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x13x4x15x24x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x13x4x15x29x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x38x27x16x2x13x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x38x27x16x2x13x4x15x24x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x15x4x13x2x16x27x38x24x13 remaining piece : 17,34
Move 13x27x36x47x38x49x35x24x15x4x13x24x38x27x16x2x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x24x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x24x35x49x38x29x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x24x35x49x38x24x15x4x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x4x15x24x38x49x35x24x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x4x15x24x35x49x38x24x13 remaining piece : 17,34
Move 13x27x36x47x38x27x16x2x13x4x15x29x38x49x35x24x13 remaining piece : 17,34
Move 13x27x16x2x13x24x38x47x36x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x24x38x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x24x35x49x38x47x36x27x38x29x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x24x35x49x38x47x36x27x38x24x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x24x35x49x38x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x24x35x49x38x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x24x38x47x36x27x38x49x35x24x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x24x38x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x24x35x49x38x47x36x27x38x24x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x24x35x49x38x27x36x47x38x24x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x29x38x47x36x27x38x49x35x24x13 remaining piece : 17,34
Move 13x27x16x2x13x4x15x29x38x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x24x38x49x35x24x15x4x13x2x16x27x38x47x36x27x13 remaining piece : 17,34
Move 13x24x38x49x35x24x15x4x13x2x16x27x38x47x36x22x13 remaining piece : 17,34
Move 13x24x38x49x35x24x15x4x13x2x16x27x36x47x38x27x13 remaining piece : 17,34
Move 13x24x38x49x35x24x15x4x13x22x36x47x38x27x16x2x13 remaining piece : 17,34
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Move 13x24x38x47x36x27x13x4x15x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x24x38x47x36x27x38x49x35x24x15x4x13x2x16x27x13 remaining piece : 17,34
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Move 13x24x38x47x36x27x16x2x13x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x24x38x47x36x27x16x2x13x4x15x24x35x49x38x27x13 remaining piece : 17,34
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Move 13x24x38x47x36x22x13x4x15x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x24x38x27x13x2x16x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x24x38x27x13x4x15x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
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Move 13x24x35x49x38x47x36x27x16x2x13x27x38x29x15x4x13 remaining piece : 17,34
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Move 13x24x35x49x38x47x36x22x13x2x16x27x38x29x15x4x13 remaining piece : 17,34
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Move 13x24x35x49x38x27x13x2x16x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x13x2x16x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x13x4x15x24x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x24x35x49x38x27x13x4x15x29x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x24x35x49x38x27x36x47x38x29x15x4x13x2x16x27x13 remaining piece : 17,34
Move 13x24x35x49x38x27x36x47x38x29x15x4x13x27x16x2x13 remaining piece : 17,34
Move 13x24x35x49x38x27x36x47x38x24x15x4x13x2x16x27x13 remaining piece : 17,34
Move 13x24x35x49x38x27x36x47x38x24x15x4x13x27x16x2x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x22x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x22x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x27x36x47x38x29x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x27x36x47x38x24x15x4x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x4x15x24x38x47x36x27x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x4x15x24x38x47x36x22x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x4x15x29x38x47x36x27x13 remaining piece : 17,34
Move 13x24x35x49x38x27x16x2x13x4x15x29x38x47x36x22x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x38x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x38x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x38x49x35x24x38x47x36x27x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x38x49x35x24x38x47x36x22x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x36x47x38x24x35x49x38x27x13 remaining piece : 17,34
Move 13x24x15x4x13x2x16x27x36x47x38x49x35x24x38x27x13 remaining piece : 17,34
Move 13x24x15x4x13x22x36x47x38x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x24x15x4x13x22x36x47x38x49x35x24x38x27x16x2x13 remaining piece : 17,34
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Move 13x24x15x4x13x27x36x47x38x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x24x15x4x13x27x36x47x38x49x35x24x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x38x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x38x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x38x49x35x24x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x38x49x35x24x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x36x47x38x24x35x49x38x27x13 remaining piece : 17,34
Move 13x4x15x24x13x2x16x27x36x47x38x49x35x24x38x27x13 remaining piece : 17,34
Move 13x4x15x24x13x22x36x47x38x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x22x36x47x38x49x35x24x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x27x38x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x27x38x49x35x24x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x27x36x47x38x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x13x27x36x47x38x49x35x24x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x2x16x27x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x2x16x27x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x2x16x27x36x47x38x27x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x22x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x27x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x49x35x24x13x27x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x38x49x35x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x38x49x35x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x16x2x13x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x27x16x2x13x24x35x49x38x27x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x22x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x47x36x22x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x27x13x2x16x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x27x13x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x27x36x47x38x49x35x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x24x38x27x36x47x38x49x35x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x38x27x16x2x13x22x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x27x16x2x13x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x24x38x27x16x2x13x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x38x27x16x2x13x24x35x49x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x2x16x27x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x2x16x27x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x2x16x27x36x47x38x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x22x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x27x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x24x13x27x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x13x2x16x27x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x13x24x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x38x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x38x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x16x2x13x27x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x27x16x2x13x24x38x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x22x13x2x16x27x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x47x36x22x13x24x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x13x2x16x27x36x47x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x13x24x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x36x47x38x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x36x47x38x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x16x2x13x22x36x47x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x16x2x13x27x36x47x38x24x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x16x2x13x24x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x24x35x49x38x27x16x2x13x24x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x2x16x27x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x2x16x27x38x47x36x22x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x2x16x27x36x47x38x27x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x22x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x27x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x49x35x24x13x27x36x47x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x38x49x35x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x38x49x35x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x16x2x13x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x27x16x2x13x24x35x49x38x27x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x22x13x2x16x27x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x47x36x22x13x24x35x49x38x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x27x13x2x16x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x27x13x24x35x49x38x47x36x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x27x36x47x38x49x35x24x13x2x16x27x13 remaining piece : 17,34
Move 13x4x15x29x38x27x36x47x38x49x35x24x13x27x16x2x13 remaining piece : 17,34
Move 13x4x15x29x38x27x16x2x13x22x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x27x16x2x13x27x36x47x38x49x35x24x13 remaining piece : 17,34
Move 13x4x15x29x38x27x16x2x13x24x35x49x38x47x36x27x13 remaining piece : 17,34
Move 13x4x15x29x38x27x16x2x13x24x35x49x38x47x36x22x13 remaining piece : 17,34

[TAILLE]

For the sceptics, the 312 PDN 3.0 standard notations for the move 13x21x30x13 which reach the unique position B:WK13:B17,34

Move 13x2x16x27x13x24x38x47x36x27x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x38x27x36x47x38x49x35x24x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x47x36x27x38x29x15x4x13 remaining piece : 17,34
Move 13x2x16x27x13x24x35x49x38x47x36x27x38x24x15x4x13 remaining piece : 17,34
...

Oops the last proposal here above is not allowed by the PDN 3.0 standard, is it?
Julien, can you explain why it is a problem to have a lot of possible notations for a given move? Different players may well play the same move with different sequences of captures and it is the reality of the game, isn't it.

Gérard

[julien007]

The only problem is that you can never compare PDN files without strong calculations to compare games !

Are PDN files made for journalists or novelists to describe the course of the game or for players studying the positions ?

[Wieger Wesselink]

Indeed the rules in PDN 3.0 do not enforce a unique notation of ambiguous moves. That is unfortunate, but it was not considered as a real problem when developing the standard. What I can do is to add a recommendation to choose the notation that is the lexicographically smallest of all possible notations. Does that seem like a useful approach?

[TAILLE]

Hi,

Indeed the rules in PDN 3.0 do not enforce a unique notation of ambiguous moves. That is unfortunate, but it was not considered as a real problem when developing the standard. What I can do is to add a recommendation to choose the notation that is the lexicographically smallest of all possible notations. Does that seem like a useful approach?

I do not see clearly how we can reach a unique notation of ambiguous moves.
FYI Damy accepts the following non ambiguous notations for the move taking the 9 and 20 men:
48x3x48, 48x9x48, 48x14x48, 48x20x48 and 48x25x48
as well as a large number of longest notations.
When building a PDN file Damy generates here : 48x25x14x3x26x48

[julien007]

1/- Positions change are best described with the captures than with the «turning points» (the path is a means to reach the target, the captures are visible changes, some turning points are conventionnal... ).

2/ - In case of necessary disambiguation, the only original captures (those that are not present in all possible notations of the same position change) are significant and have to be used in the notation. Here is a first critical choice to retain all pieces or only useless pieces...

3/- As Gerard rightly points out, a problem of permutation can subsist. In my opinion, there is only a matter of convention. The simpler seems, if (and only if) the different moves are possible, to chose the natural order and permute the cell number's string to start with the smallest number.

Then the two possible moves of Gérard's last example would be noted 48x9x20x48 or 48x17x24x48 rather than 48x20x9x48 and 48x24x17x48. Unless a more concise notation retains preferences with 48x9x48 or 48x17x48(*). In current cases, it's seems that the longest notation would be more descriptive and easier to define...

To define a single notation it would be critical to choose between this two notations !
Even if the machines have to read several notations. They must know how to write the right unique official notation.

In this condition, a unique notation for each move can be defined and the unique notation 13x21x30x13 will then describe the 312 pseudo-variants(**) of the above caricatural example.

Sincerely yours.
Julien de Prabère

(*) In this cases the pieces 20, obligatory after 9, and 24, obligatory after17, are not necessary to describe the move.

(**) In this case, there is obviously two possible ways (each with 156 moves) : 13x21x30x13 and 13x30x21x13. We choose the first by convention.

[Wieger Wesselink]

Hi,

Indeed the rules in PDN 3.0 do not enforce a unique notation of ambiguous moves. That is unfortunate, but it was not considered as a real problem when developing the standard. What I can do is to add a recommendation to choose the notation that is the lexicographically smallest of all possible notations. Does that seem like a useful approach?

I do not see clearly how we can reach a unique notation of ambiguous moves.
FYI Damy accepts the following non ambiguous notations for the move taking the 9 and 20 men:
48x3x48, 48x9x48, 48x14x48, 48x20x48 and 48x25x48
as well as a large number of longest notations.
When building a PDN file Damy generates here : 48x25x14x3x26x48

What I meant is that it is recommended to choose the capture with the lexicographically smallest long notation. So in your example the capture 48x25x14x3x26x48 would be preferred over 48x26x3x14x25x48. This is a unique notation of ambiguous moves.

[Wieger Wesselink]

1/- Positions change are best described with the captures than with the «turning points» (the path is a means to reach the target, the captures are visible changes, some turning points are conventionnal... ).

2/ - In case of necessary disambiguation, the only original captures (those that are not present in all possible notations of the same position change) are significant and have to be used in the notation. Here is a first critical choice to retain all pieces or only useless pieces...

3/- As Gerard rightly points out, a problem of permutation can subsist. In my opinion, there is only a matter of convention. The simpler seems, if (and only if) the different moves are possible, to chose the natural order and permute the cell number's string to start with the smallest number.

Then the two possible moves of Gérard's last example would be noted 48x9x20x48 or 48x17x24x48 rather than 48x20x9x48 and 48x24x17x48. Unless a more concise notation retains preferences with 48x9x48 or 48x17x48(*). In current cases, it's seems that the longest notation would be more descriptive and easier to define...

To define a single notation it would be critical to choose between this two notations !
Even if the machines have to read several notations. They must know how to write the right unique official notation.

In this condition, a unique notation for each move can be defined and the unique notation 13x21x30x13 will then describe the 312 pseudo-variants(**) of the above caricatural example.

Sincerely yours.
Julien de Prabère

(*) In this cases the pieces 20, obligatory after 9, and 24, obligatory after17, are not necessary to describe the move.

(**) In this case, there is obviously two possible ways (each with 156 moves) : 13x21x30x13 and 13x30x21x13. We choose the first by convention.

I understand that it is possible to use squares of captured pieces instead of turning points. It is a different approach, but I don't think it is clearly better than the current approach. An advantage of using captured squares is that there are less possibilities. A disadvantage is that it is highly unusual. I have never seen a notation like 48x9x20x48 in practice. Both approaches do not guarantee a unique notation.

I don't like the idea to sort the captured squares to make the notation unique. I think it is confusing if the captured squares are not in the same order as the corresponding legal move. Therefore I would prefer to choose the lexicographically smallest notation. So in Gérard's example this would be 48x20x9x21x42x48 and not 48x42x21x9x20x48.

I don't like the idea to leave out captured squares if they are not needed to make the move unique. If you do that, a move generator is needed to reconstruct the move. Note that ambiguous moves happen only in rare cases, so why would one bother to leave out a few squares? Note that in the discussion about PDN 3.0 the idea to allow leaving out turning points was rejected.

[TAILLE]

Hi,

Indeed the rules in PDN 3.0 do not enforce a unique notation of ambiguous moves. That is unfortunate, but it was not considered as a real problem when developing the standard. What I can do is to add a recommendation to choose the notation that is the lexicographically smallest of all possible notations. Does that seem like a useful approach?

I do not see clearly how we can reach a unique notation of ambiguous moves.
FYI Damy accepts the following non ambiguous notations for the move taking the 9 and 20 men:
48x3x48, 48x9x48, 48x14x48, 48x20x48 and 48x25x48
as well as a large number of longest notations.
When building a PDN file Damy generates here : 48x25x14x3x26x48

What I meant is that it is recommended to choose the capture with the lexicographically smallest long notation. So in your example the capture 48x25x14x3x26x48 would be preferred over 48x26x3x14x25x48. This is a unique notation of ambiguous moves.

Thank your Wieger, now I understand your proposal and I see we can effectively build a unique notation.
For a theoritical point of view it is very interresting to have a unique notation but for a practical point of view I still do not see any need for that. I never compared two PDN files referring to the same game. Should this happen it's highly improbable that this game includes an ambiguous move, is it? Even in that case, if you compare two PDN files referring to two games played by the same players in the same tournament with all moves identical except the notation of an ambiguous move do you doubt it could be two different games?

I have another point: it would be a pity to build a recommandation that could be very difficult for a human to apply. Any program could easily list all possible notations and choose the lexicographically smallest long notation. For a human it could be a nithmare if hundreds of long notations exist. With this point in mind I prefer to let any program choose any long notation.

BTW Wieger, I do not understand your point concerning the non-use of a move generator. In case of a long and non ambiguous capture you need a move generator because the notation give you only the origin and the destination squares, don't you?

[julien007]

I maintain that the path or «turning points» belongs to literature rather than the position of the game.

I never propose to sort the captured squares to make the notation unique (it was only to easily compare the captured pieces in a draft). I only propose to prefer the natural order for the first cell number when two orders are possible with a sub-sequence and the same sequence in reverse order.

I am a neophyte with Draughts... I find all sort of rules of disambiguation on the web. Nothing in the official rules and only two examples of disambiguation which do not apply the standards and do not apply the same rules (next to chess, it's a little messy) :

[Event "Championnats de France 2012"]
[Site "?"]
[Date "2012.08.14"]
[Round "?"]
[White "Arendo,Marc"]
[Black "D'Almeida,Jean"]
[Result "0-1"]
[GameType "20"]
[PlyCount "92"]

[Event "Championnats de France 2012"]
[Site "?"]
[Date "2012.08.14"]
[Round "?"]
[White "Arendo,Marc"]
[Black "D'Almeida,Jean"]
[Result "0-1"]
[GameType "20"]
[PlyCount "92"]

1. 34-29 19-23 2. 40-34 14-19 3. 45-40 10-14 4. 50-45 5-10 5. 31-26
20-24 6. 29x20 15x24 7. 32-28 23x32 8. 37x28 18-23 9. 38-32 10-15
10. 41-37 12-18 11. 46-41 7-12 12. 42-38 1-7 13. 34-29 23x34
14. 40x20 15x24 15. 47-42 18-23 16. 44-40 12-18 17. 39-34 7-12
18. 43-39 17-21 19. 26x17 11x22 20. 28x17 12x21 21. 49-43 8-12
22. 33-28 4-10 23. 34-30 10-15 24. 36-31 21-26 25. 30-25 12-17
26. 31-27 17-21 27. 39-33 14-20 28. 25x14 9x20 29. 43-39 2-8
30. 41-36 8-12 31. 39-34 3-8 32. 34-30 20-25 33. 28-22 25x34
34. 40x20 15x24 35. 33-28 23-29 36. 45-40 18-23 37. 48-43 12-17
38. 22x11 6x17 39. 27-22 24-30 40. 35x33 19-24 41. 28x30 17x48
42. 30-25 26-31 43. 37x17 48x45x42x17x40 44. 25-20 45-23 45. 32-27
8-12 46. 20-15 13-18
0-1

The position before 43. ... 48x45x42x17x40

I propose only to write : 48x17x45


[Event "Open National de Cannes 2012"]
[Site "Cannes"]
[Date "2012.02.14"]
[Round "3"]
[White "Olivan, Thomas"]
[Black "Farcy, Jean-Louis"]
[Result "1/2-1/2"]

1. 32-28 17-21 2. 37-32 21-26 3. 41-37 16-21 4. 34-30 11-16 5. 30-25 19-23 6.
28x19 14x23 7. 25x14 10x19 8. 31-27 7-11 9. 35-30 12-17 10. 40-35 5-10 11.
33-28 17-22 12. 28x17 11x31 13. 36x27 10-14 14. 39-33 1-7 15. 33-28 15-20 16.
38-33 7-11 17. 43-38 20-24 18. 44-39 8-12 19. 46-41 12-17 20. 49-43 17-22 21.
28x17 11x31 22. 41-36 2-7 23. 36x27 7-11 24. 50-44 4-10 25. 47-41 10-15 26.
41-36 14-20 27. 30-25 11-17 28. 25x14 9x20 29. 33-28 20-25 30. 44-40 3-8 31.
40-34 24-29 32. 39-33 29x40 33. 45x34 17-22 34. 28x17 21x12 35. 33-29 19-24
36. 29x20 15x24 37. 43-39 24-30 38. 35x24 23-28 39. 32x23 18x40 40. 48-43
40-45 41. 38-32 12-18 42. 39-34 18-23 43. 43-39 26-31 44. 37x26 45-50 45.
34-29 50x28x48 46. 29x9 48-39 47. 9-4 39-11 1/2-1/2


The position before 45. ... 50x28x48

I propose only to write 50x32x48

These proposals seem to respond to practices (short notation, I doubt that competitors like having to mention a long list of most often unnecessary numbers) and seem very simple to enunciate :

Disambiguated capture sequences have to specify the specific captured pieces of the move.
In case of cycle, with two possible orders for a sub-sequence, chose the order which begin with the smallest number of cell.

In any case, clarification and recommendations are desirable and have to figure in the official rules.

[Wieger Wesselink]

Thank your Wieger, now I understand your proposal and I see we can effectively build a unique notation.
For a theoritical point of view it is very interresting to have a unique notation but for a practical point of view I still do not see any need for that. I never compared two PDN files referring to the same game. Should this happen it's highly improbable that this game includes an ambiguous move, is it? Even in that case, if you compare two PDN files referring to two games played by the same players in the same tournament with all moves identical except the notation of an ambiguous move do you doubt it could be two different games?

I have another point: it would be a pity to build a recommandation that could be very difficult for a human to apply. Any program could easily list all possible notations and choose the lexicographically smallest long notation. For a human it could be a nithmare if hundreds of long notations exist. With this point in mind I prefer to let any program choose any long notation.

BTW Wieger, I do not understand your point concerning the non-use of a move generator. In case of a long and non ambiguous capture you need a move generator because the notation give you only the origin and the destination squares, don't you?

Hi Gérard, you are right that it is mostly a theoretical issue to have a unique notation for ambiguous moves. Nevertheless I think it is useful to have a recommendation for a unique notation. Then people who want to have a unique notation can use it, but it should not be a requirement for the PDN standard. Note that this is only interesting for programmers. Human players should never have to worry about finding the lexicographically smallest notation.

Indeed my concern about the need for a move generator does not make sense. It forgot that it is already needed for non-ambiguous captures.

[Wieger Wesselink]

I maintain that the path or «turning points» belongs to literature rather than the position of the game.

I never propose to sort the captured squares to make the notation unique. I only propose to prefer the natural order when two orders are possible.

I am a neophyte with Draughts... I find all sort of rules of disambiguation on the web. Nothing in the official rules and only two examples of disambiguation which do not apply the standards and do not apply the same rules (next to chess, it's a little messy) :

[Event "Championnats de France 2012"]
[Site "?"]
[Date "2012.08.14"]
[Round "?"]
[White "Arendo,Marc"]
[Black "D'Almeida,Jean"]
[Result "0-1"]
[GameType "20"]
[PlyCount "92"]

[Event "Championnats de France 2012"]
[Site "?"]
[Date "2012.08.14"]
[Round "?"]
[White "Arendo,Marc"]
[Black "D'Almeida,Jean"]
[Result "0-1"]
[GameType "20"]
[PlyCount "92"]

1. 34-29 19-23 2. 40-34 14-19 3. 45-40 10-14 4. 50-45 5-10 5. 31-26
20-24 6. 29x20 15x24 7. 32-28 23x32 8. 37x28 18-23 9. 38-32 10-15
10. 41-37 12-18 11. 46-41 7-12 12. 42-38 1-7 13. 34-29 23x34
14. 40x20 15x24 15. 47-42 18-23 16. 44-40 12-18 17. 39-34 7-12
18. 43-39 17-21 19. 26x17 11x22 20. 28x17 12x21 21. 49-43 8-12
22. 33-28 4-10 23. 34-30 10-15 24. 36-31 21-26 25. 30-25 12-17
26. 31-27 17-21 27. 39-33 14-20 28. 25x14 9x20 29. 43-39 2-8
30. 41-36 8-12 31. 39-34 3-8 32. 34-30 20-25 33. 28-22 25x34
34. 40x20 15x24 35. 33-28 23-29 36. 45-40 18-23 37. 48-43 12-17
38. 22x11 6x17 39. 27-22 24-30 40. 35x33 19-24 41. 28x30 17x48
42. 30-25 26-31 43. 37x17 48x45x42x17x40 44. 25-20 45-23 45. 32-27
8-12 46. 20-15 13-18
0-1

The position before 43. ... 48x45x42x17x40

I propose only to write : 48x17x45


[Event "Open National de Cannes 2012"]
[Site "Cannes"]
[Date "2012.02.14"]
[Round "3"]
[White "Olivan, Thomas"]
[Black "Farcy, Jean-Louis"]
[Result "1/2-1/2"]

1. 32-28 17-21 2. 37-32 21-26 3. 41-37 16-21 4. 34-30 11-16 5. 30-25 19-23 6.
28x19 14x23 7. 25x14 10x19 8. 31-27 7-11 9. 35-30 12-17 10. 40-35 5-10 11.
33-28 17-22 12. 28x17 11x31 13. 36x27 10-14 14. 39-33 1-7 15. 33-28 15-20 16.
38-33 7-11 17. 43-38 20-24 18. 44-39 8-12 19. 46-41 12-17 20. 49-43 17-22 21.
28x17 11x31 22. 41-36 2-7 23. 36x27 7-11 24. 50-44 4-10 25. 47-41 10-15 26.
41-36 14-20 27. 30-25 11-17 28. 25x14 9x20 29. 33-28 20-25 30. 44-40 3-8 31.
40-34 24-29 32. 39-33 29x40 33. 45x34 17-22 34. 28x17 21x12 35. 33-29 19-24
36. 29x20 15x24 37. 43-39 24-30 38. 35x24 23-28 39. 32x23 18x40 40. 48-43
40-45 41. 38-32 12-18 42. 39-34 18-23 43. 43-39 26-31 44. 37x26 45-50 45.
34-29 50x28x48 46. 29x9 48-39 47. 9-4 39-11 1/2-1/2


The position before 45. ... 50x28x48

I propose only to write 50x32x48

These proposals seem to respond to practices (short notation) and seem very simple to enunciate :

Disambiguated capture sequences have to specify the specific captured pieces of the move.
In case of cycle, with two possible orders for a sub-sequence, chose the order which begin with the smallest number of cell.

In any case, clarification and recommendations are desirable and have to figure in the official rules.

Hi Julien, sorry that I misunderstood your point about sorted orders. Your formulation of disambiguated capture sequences does not look exact, since "a cycle with two possible orders for a sub-sequence" is not a well-defined notion. If you want to make it precise, you can use something like lexicographical ordering. To give an exact definition of a unique short notation takes even more effort.

Anyhow, as long as there are no official rules for the notation, I don't think there is a reason to change the PDN standard. Perhaps the current formulation should be improved. I'm open for suggestions.