[Retros] Mushikui Reconstruction

Francois Labelle flab at wismuth.com
Fri May 20 11:36:34 EDT 2011

On Fri, 2011-05-20 at 08:48 -0500, Mu-Tsun Tsai wrote:

> The idea of mushikui reconstruction is the following. A score of a chess

> game, written in PGN format, is presented. However all the characters are

> concealed by "*" symbols, so that only the length of the representation of

> each move is known to the solvers. For example "Qxd2+" will become "*****",

> and "cxd6ep" will become "******", etc.

Hi Mu-Tsun,

The PGN spec is at http://www.chessclub.com/help/PGN-spec and says that
"En passant captures do not have any special notation". So cxd6ep is
written "cxd6" in PGN. This can be confirmed by playing a game with en
passant in any chess program and saving the game as PGN.

Other things to look for: PGN specifies the use of # for checkmate (not
++), the use of "=" to denote promotion, the notations O-O and O-O-O for
castling (not OO and OOO), and gives precise disambiguation rules when
multiple pieces of the same type can move to the same square (e.g.
Raxa3). All of these subtleties affect the number of stars.

So I suggest you base the reconstruction on the exact PGN spec (sorry if
this invalidates some of the problems you've constructed so far), or
that you explicitly list all the deviations your format has compared to


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