U.S. analysts discovered no hint in PURPLE of the impending Japanese attack on Pearl Harbor; nor could they, as the Japanese were very careful not to discuss their plan in Foreign Office communications. In fact, no detailed information about the planned attack was even available to the Japanese Foreign Office, as that agency was regarded by the military, particularly its more nationalist members, as insufficiently "reliable". U.S. access to private Japanese diplomatic communications (even the most secret ones) was less useful than it might otherwise have been because policy in prewar Japan was controlled largely by military groups like the Imperial Way Faction, and not by the Foreign Office. The Foreign Office itself deliberately withheld from its embassies and consulates much of the information it did have, so the ability to read PURPLE messages was less than definitive regarding Japanese tactical or strategic military intentions.