As the manual is a little unclear in the subject.

F1 brings up a list of your opponents
F2 brings up a map of Japan
F3 brings up a menu of what your rivals are up to and any possible tasks that need completion.
Alt-S allows you to save
Alt-R allows you to restore
Alt-Q makes you quit to DOS

Thanks

What about the keys for duel combat? I can't figure out which keys I'm supposed to use for those.

In duels you move, parry and attack with the cursor keys: left, right, up, down

To enter parry mode, hold the Backspace key.
Now pressing left or right yields a parrying position in this direction.

To enter attack mode, hold the Return key.

Tree basic options to strike:
1. Basic strike: Press either left, right, upper left, up or upper right
2. Swinging horizontal: Strike out by pressing left or right and swing the sword by pressing the opposite direction.
3. Force a powerful hack, that can't be parried. Strike out as far as possible, by pressing and holding either lower left, down or lower right. Then hack by releasing the strike out key or by pressing one of the up keys (upper left, up, upper right). It's a slow technique, that leaves you vulnerable during the strike out phase.

Tip: You can try to lure your opponent within your reach, while waiting in a position for a powerful hack. Lift the sword on the side from where the opponent approaches to reach him as soon as possible. Once he's near enough, just release the strike out key to hack down. Be careful, when you've missed, as the opponent is now in range to strike himself.

Hitting the Spacebar pauses/resumes a duel.

Thank you, DeMignon!

I have encountered another difficulty. In battle mode, I know that the arrow keys means to switch turns or formations, the Enter key to start, and the R key for retreat. When I am in a position where the next attack is up to me, I don't know how to get my remaining forces to attack. Could you also tell me the keys for those? (I know that if I press Enter on my troops with the fan, it results in a line that could stretch, but I can't make the line stop or do anything when I press Enter again.)

It infuriates me that the manual doesn't mention the keys. There's supposed to be a Technical thingy that would show me the keys, but it's not in the manual or with the game. It's listed in the index of the manual, but no page number. Urgh!

Wait a minute: they did include the technical supplement in the download section. Boy, am I red!

;-) I hope it became clearer now. Anyway, there is also a good tactic for battles where you are attacking.

The enemy AI is rather stupid and holds all units in place. What you can do is marching with one line directly in front of an enemy unit, but stop it if it automatically starts to charge. Now take another unit and position it in the flank or slightly behind the enemy and start to attack Because of your first unit standing right in front of him he doesn't turn around and your attacking troops don't take damage when attacking from the side or behind. When he turned halfway for defense, attack with the first unit too.

The best thing is, that all other enemy units only watch, as long as you don't come too close to them. This way you can pick out one unit after another and win a battle in which you are clearly outnumbered.

In large battles during the later stages of the game, this becomes tedious and unpractical. Now, you have to use classical war strategies, by choosing the right starting formation and the main focus of attack. Your goal is to find the enemy's weak points in his formation and hit him hard, so that his troops begin to flee. Keep in mind the effects of flanking and terrain as well as unit bonuses against certain opponents. You still may want to stop some of your units short before they attack, to keep the enemy in place for other units to attack. Done right, battles can be played quite quickly, by a massive attack in the right spot.

Use the number keys, to quickly change between units and distributing commands.

Just for the completion of this thread:

In battle mode, in order to move one's troops, press the number corresponding the troop you wish to move (1, 2, 3 etc.). The plus key will make them move to where you move the cursor, and the minus key will make them move without changing the direction they're facing.