Reciprocal zugzwangs with not more than six men.

John Beasley's contribution to this exercise has been entirely cosmetic, and his thanks are due to Guy Haworth for the data from which the PGN file was generated.

Guy in turn makes extensive acknowledgements, citing initials which I read as referring to Eiko Bleicher, Marc Bourzutschky, Peter Karrer, Eugene Nalimov, John Tamplin, Ken Thompson, and Christoph Wirth, and I am sure that tracing back down the literature would identify further workers whose contributions, though now duplicated or overtaken, were significant advances at the time.

Here you can download the zip-file with the PGN and PDF file shown below.

A few rows from the PGN-file shown: