[Retros] 6 e8=R#

[Noam Elkies]

Andrew Buchanan writes:


> It turns out that in *5* cases, our homespun results can be improved upon:


(NB even these "homespun" results are computer-assisted by Natch or Popeye...)


> Piece Line  Ours Actual

> [...]

> R       e       13      11

> [...]


Pin-mates to the rescue:

  1 e4 d6(d5)  2 Qg4 Bf5  3 exf5 Qd7  4 f6 Kd8  5 fxe7+ Kc8  6 e8=R#

(both versions C+ Popeye in under a second).

Mario -- you didn't specify whether "realizable" means in a sound
proof game or in an unrestricted game, but now I see it must have been
the former because g7-g8Q(R)# can be easily shown in 11 ply without
the soundness condition, e.g. 1 g4 g6 2 g6 Nh6 3 gxh6 Bg7 4 hxg7 h5
5 random Rh7 6 g8R#.  Did you keep track of how many sound proof games
each minimally "realizable" promotion mate had?

--Noam D. Elkies