[Retros] "half" proof games

[Richard Stanley]

Regarding Joost's claimed dual to my game starting  1.g4 ... 2.gxh5
... 3.hxg6, Noam wrote:


> Joost suggests that Richard's game starting 1 g4 ... 2 g:h5 ... 3

> h:g6 is cooked because Black could play either g5 or g6 on his 2nd

> move.  Again this is a matter of exactly which notation system is

> used; in the system that uses "2...g5 3 h:g6 ep", either 3 h:g6 or 3

> h:g6 ep would have a unique solution.


I suppose that one authoritative source for chess notation is the
Portable Game Notation Specification, Section 8.2.3. See
www.chessclub.com/help/PGN-spec. In subsection 8.2.3.3 it states that
"en passant captures do not have any special notation ..." Thus
according to this source, Joost is correct that my problem is
dualized. Here is a possible alternative, though if my original
problem really does have 481 solutions (not a result of the typo
11.B6d8), then I'm not so confident about the soundness of the
following. (I'll omit the ... for Black's moves.)

1.g4 2.gh5 3.h4 4.Rxh4 5.Rxh6 6.Rxf6 7.Rxb6 8.Rxg6 9.Rg8+ 10.Rxf8+
11.d3 12.Bd2 13.Ba5 14.Bxd8 15.Qc1.

Another ending is 11.f4 12.fe5.

In either version, the moves 6.Rxf6 7.Rxb6 merely extend the
solution and can be omitted if necessary for soundness. 

Richard