[Retros] shortest proofgames of castling switchback

[Hirokaz ONODA]

Hi,

I searched games at www.softdecc.de/pdb/search.pdb and added 3 games to the
list below. 


The shortest PG for castling switchback:
invader: a promoted Rook
(7.5, 1) 1.e4 f5 2.Bc4 f4 3.Ne2 f3 4.0-0 fxe2 5.f3 e1=R 6.Kf2 Re3 7.Rh1 Rd3
8.Ke1 (Joost de Heer, 10/2/2005)

invader: a Queen
(7.5, 5) 1.e3 d6 2.Bb5 Qd7 3.Ne2 Qxb5 4.0-0 Qxe2 5.f3 Qxd1 6.Kf2 Qxc1 7.Rh1
Qe1 8.Kxe1 (Andrew Buchanan, 11/2/2005)
 
invader: a Knight
(8.5, 2) 1.g3 f5 2.Bh3 f4 3.Bxd7 Nxd7 4.Nh3 Ne5 5.O-O Nf3 6.Kg2 e5 7.Rh1
Ng1 8.Kf1 f3 9. Ke1 (Ayako Okaya, Problem Paradise 13 1999)

invader: a promoted Queen
(9.0, 3) 1. e4 f5 2. Bd3 f4 3. Ne2 f3 4. 0-0 fxe2 5. f4 e1=Q 6. Qe2 Qxd2 7.
Kf2 Qa5 8. Rh1 Qxa2 9. Ke1 Qf7 (Markus Ott, Themes-64 1981)

invader: a King
(15.0, 5) 1. d4 d6 2. Kd2 Qd7 3. Ke3 Qh3+ 4. Kf4 g5+ 5. Kxg5 e5 6. d5 Be6
7. dxe6 Ne7 8. Qd5 f6+ 9. Kxf6 Bh6 10. Nd2 0-0+ 11. Kxe7 Rxf2 12. Kd8 Kf8
13. Kc8 Ke8 14. Rb1 Rf8 15. Ngf3 Rh8 (Hirokaz Onada, The Problemist 1991)

Captureless: vacant

Q-side castling switchback:
(15.5, 2) 1. d3 d5 2. Be3 d4 3. Nd2 dxe3 4. Nb3 Qd4 5. Qd2 Bd7 6. 0-0-0
exd2+ 7. Kb1 Qe3 8. Rc1 d1=R 9. d4 Rd3 10. Rd1 Rc3 11. Rd2 Rc6 12. Kc1 Rd6
13. Kd1 Bc6 14. Ke1 Nd7 15. Rd1 0-0-0 16. Ra1 (Andrey Frolkin, diagrammes
94 07-09/1990)

cf.(after O-O-O, K returns, but R does not):
1.d4 c5 2.Bh6 cxd4 3.Qxd4 Nxh6 4.Nd2 Nf5 5.0-0-0 Nxd4 6.Re1 Nxc2 7.Kd1 Nxe1
8.Kxe1 (Christoph Fieberg, 2005)

Castling switchback for both sides:
(19.0, 3) 1. e4 c5 2. Bd3 c4 3. Ne2 cxd3 4. 0-0 dxe2 5. c4 e1=R 6. c5 Re3
7. c6 Rf3 8. c7 Rf4 9. f3 e5 10. Kf2 Bc5+ 11. Ke1 Ne7 12. Rh1 0-0 13.
cxd8=R Nec6 14. Re8 Nd8 15. Re6 Nbc6 16. Rg6 f6 17. Rg3 Kf7 18. Qb3+ Ke8
19. Qd5 Rh8 (Andrey Frolkin, Die Schwalbe 124 08/1990)


Amici Sumus,
Hiro


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