[Retros] New Task: PG m.0 #n

[Joost de Heer]

> This suggested to me a different task. Create a PG in m.0 moves which is

> also a sound direct mate in n (>= 2) moves. This appeals to me because I

> like positions in which both retro and forward play must be considered.


Not an exact proofgame, but:

Caillaud, Loustau, Rotenberg
Phenix 10.1998
4b2r/p1P4p/1q2PB1k/r1Q1S1pP/1p6/pP1R4/P3BP2/1K
Position after black's 23rd move. #2v

1. Na3 c5 2. b3 Nc6 3. Bb2 d5 4. c4 Bd7 5. Qc2 b5 6. O-O-O Qb6 7. cxd5 
Rd8 8. dxc6 f5 9. c7 Kf7 10. Kb1 Be8 11. Nf3 Rxd2 12. g4 Rxe2 13. Rd3 
Nf6 14. Bxf6 Re5 15. h4 Kg6 16. h5+ Kh6 17. Rh4 b4 18. gxf5 bxa3 19. Rb4 
cxb4 20. Be2 Ra5 21. Ne5 e6 22. fxe6 Bc5 23. Qxc5 g5

1. Rh3? (2. Sg4#) Bg6 2. hg6# (but 1. .. Qe6!)
1. hg6ep! (2. Rh3#) Bg6 2. Sg4
Djurasevic cycle

This is an extension to:

Caillaud, Loustau, Rotenberg
Special Prize
Phenix 10.1988 (version 12.1994)
4b3/7p/4S2k/1R2S1pP/8/3R4/2K5/3B
#2v

1. hg6ep? (2. Rh3) Bg6 2. Sg4# illegal
1. Rh3! (2. Sg4) Bg6 2. hg6#
Djurasevic cycle

Joost