[Retros] 2009 problem

[Noam Elkies]

Olli Heimo <olli.heimo at luukku.com> writes:


> I notice, that Noam Elkies has not sent his usual chess-mathematical

> problem for year 2009.  Is it too difficult to get 2009 solutions [...]


No it's not too hard -- I just forgot about it, partly because
I no longer teach the chess-and-math seminar where I used my first
such problem if memory serves.  At least it's not too hard if one has
no ambitions beyond the bare numerical task; here's an example that
I cooked up over lunch, with little non-numerical content (C+ Popeye
in about a minute):


White  Re5 Sb1 Bf6 Qd3 Kg3 Bf1 Sg1 Rh1 Pa4 Pb3 Pc2 Pd2 Pe4 Pf3 Pg2 Ph2
Black  Rb8 Sa6 Bf5 Qe7 Ka8 Bf8 Sd8 Rh8 Pa7 Pb7 Pc7 Pd5 Pe6 Pf7 Pg7 Ph7

              NDE 2009

+---a---b---c---d---e---f---g---h---+

|                                   |

8  -K  -R   .  -S   .  -B   .  -R   8

|                                   |

7  -P  -P  -P   .  -Q  -P  -P  -P   7

|                                   |

6  -S   .   .   .  -P   B   .   .   6

|                                   |

5   .   .   .  -P   R  -B   .   .   5

|                                   |

4   P   .   .   .   P   .   .   .   4

|                                   |

3   .   P   .   Q   .   P   K   .   3

|                                   |

2   .   .   P   P   .   .   P   P   2

|                                   |

1   .   S   .   .   .   B   S   R   1

|                                   |

+---a---b---c---d---e---f---g---h---+
  dia12.5                   16 + 16

(Shortest) proof game in 12.5 moves: how many solutions?


Happy new year,
--NDE