[Retros] Pawn to-the-7th rank mates

[Nicolas.Dupont at math.univ-lille1.fr]

> Category A:

> b7#/...b2# etc., mate by pawn itself

>

> 1.c3 b5 2.Qa4 Bb7 3.Qxa7 Bd5 4.Qxc7 Nc6 5.Qxc6 Qc7 6.a4

> 0-0-0 7.a5 Kb8 8.a6 Qd6 9.a7# (Noam Elkies)

> ...a2# (vacant)


1.Pd2-d4   Pc7-c5   2.Dd1-d3   Dd8-a5   3.Cb1-d2   Da5xa2
4.Cd2-b3   Pa7-a5   5.Fc1-d2   Pa5-a4   6.O-O-O    Pa4-a3
7.Cb3-a1   Da2-e6   8.Rc1-b1   De6-e3   9.Td1-c1   Pa3-a2