https://www.theguardian.com/books/2019/dec/14/game-of-birds-and-wolves-simon-parkin-review

An engaging tale of how an unsung group from the Women’s Royal Naval Service helped to defeat the U-boats

This is a curious book. The publisher, though perhaps not the author, claims that it reveals how the second world war was won, but the eponymous “secret game” does not appear until page 143 and then turns out to be a training exercise for convoy escort officers. No doubt this was a useful addition to the armoury of reforms and new equipment that marked the final stages of the battle of the Atlantic, the theme of the book. But a war winner?

Simon Parkin has a declared interest in modern gaming, which may explain why he is attracted to the real gaming that navies did before and during the war to simulate oceanic operations as a means to identify faulty tactics and to recommend different ones. His focus is on the war game devised by a retired naval commander, Gilbert Roberts, for the Western Approaches headquarters in Liverpool at the height of the Atlantic struggle. The game involved “escorts” versus “U-boats” laid out on the top floor of Derby House, where the Western Approaches command had its headquarters. Roberts and a dedicated team of young Wrens used the game to show escort captains how best to be sure of sighting U-boats as they tried to sneak into the convoy stream.