[Retros] Re: "half" proof games

[Noam Elkies]

I wrote:


> 1 d3 ... 2 Bd2 ... 3 Ba5 ... 4 Bxd8 ... 5 Qc1 ...#.


Richard Stanley answered:


> This can be lengthened by a (non-thematic) prelude, e.g.,



> 1.g4 ...    2.gh5 ... 3.hg6 ... 4.g7 ... 5.gh8Q+ ...

> 6.Qxg8+ ... 7.Qxf8+ ... 8.d3 ... 9.Bd2 ... 10.Ba5 ...

> 11.B6d8 ... 12.Qc1 ...#


Neat.  If we ignore the triple-repetition rule, this can then be
lengthened arbitrarily by interpolating

  2k+5. Qg6(5,4,3,2) ... 2k+6. Qg8+ ...

(k=1,2,...,n) between moves 6 and 7.  Likewise

  7 Qg7(h8,g3,g5) ... 8 Q:e5+ ... 9 Qh8+ ... 10 Qe5+ ... 11 Qh8+ ...
  etc. and eventually Q:e7(f8)+ ... f3(f4) ...#

NDE