[Retros] shortest proofgames of castling switchback

[Noam Elkies]

> Congratulations Noam!



> So, up to now:



> [...] Captureless: 



> (20.5, 0) 1. g3 a5 2. Bg2 Ra6 3. Be4 Rf6 4. Nf3 d6 5. 0-0 Qd7

> 6. Kh1 Qh3 7.  Rg1 Qf1 8. b3 Bh3 9. Ba3 Rf5 10. Qc1 f6 11. Qb2 Kf7

> 12. Qd4 Kg6 13. Nc3 Qb1 14. Bc1 Kh5 15. Rg2 g6 16. Kg1 Bh6 17. Kf1 Bg5

> 18. Ke1 Nh6 19. Rg1 Re8 20.  Rh1 Ng8 21. Ng1 (Noam D. Elkies, 17/7/2007)


Thanks.  Note that for task purposes this is (19.5, 0) because 20 Rh1
completes the Castling switchback.

NDE