[Retros] another 8th rank mate

[Richard Stanley]

An improvement to 


> B    dxe


  1.a2-a4 c7-c5     2.a4-a5 c5-c4     3.a5-a6 c4-c3   
  4.Ra1-a5 Qd8*a5   5.f2-f3 c3*d2 +   6.Ke1-f2 Qa5-c3   
  7.Qd1-e1 d2*e1=B  

Richard