Empires of Spymasters: The Secret War Between the British Empire and Imperial Japan, 1900-1941

‘The Empire is the Master [in the Far East] and they are the guests,’ Yamagata Aritomo, the chief imperial strategist in Tokyo, once remarked.

From the early 1900s, Imperial Japan aimed for hegemony in the Far East. During this time, resourceful and independent-minded Japanese spymasters focused on acquiring intelligence of advanced naval and aviation technology.

In London, the War Office and the Foreign Office opted for an alliance treaty with Japan. Nonetheless strategists soon realised tha...