An interesting document, however, I believe it to be phony. The data about the defenses of Manila do not ring true, although I may be wrong about that. With reference to Guam, there were only something like 150 US Marines in the 1941 garrison, not 3,000, and there were no real naval facilities, nor fortresses there before the Japanese invaded. This text also makes reference to Japanese subs patrolling the West Coast of the United States and attacking US "commercial shipping"; that was most certainly NOT pre-war Japanese doctrine. The IJN planned to use it's subs almost exclusively to support fleet actions, not as commerce raiders. It does not make sense that the Japanese Navy would publish a "book" about it's military plans and then allow Japanese Army officers to leave such a book in a hotel room. It's unlikely the IJN would even tell the IJA what it intended to do in case of war with the US. The Japanese Naval General Staff didn't even have a full time intelligence officer (let alone staff section) until just before the war started in 1941, and it certainly didn't exchange naval intelligence information with the Japanese Foreign Ministry, so the introductory information is immediately suspect.