[Retros] shortest proofgames of castling switchback

[Joost de Heer]

> Btw., does an SPG exist, where both sides did an invisible castling?


Yes, it's even in the FIDE album.

A. Frolkin
Die Schwalbe 1990
2nd prize
r1bsk2r/pp1p2pp/2s2p2/2bQp3/4Pr2/5PR1/PP1P2PP/RSB1K2R
SPG 19.0

Joost