Many of the AI's behavioral patterns are, according to the developers, based on the ideas and tactics formulated by Sun Tzu in "The Art of War." The game also displays various quotes from the book during the course of the game.
You can move an army from any province with a port to any province with a port (not necessarily adjacent) if you first move a shinobi, ninja, or emissary there first (you have to wait one season to move the army in). Also, you can move the shinobi, ninja, or emissary directly from port to port! It's a good thing the computer doesn't use this strategy!
The game shipped with all kinds of manuals ranging from very poor to ok. The Finish release had 2 tech charts, but one was in Swedish and one in Danish. I guess EA thought that Finns really do speak two languages. Luckily the manual at least was also in English.
The issue of flimsy hardcopy documentation for Shogun was further compounded by the fact that the European english release is an 88-page manual that contains more information and a poster technology tree chart, while the North American release weighs in at only 55 pages with no additional material.