The Shadow of Yesterday is unlike a lot of other fantasy roleplaying games which fetishize weaponry. You know the ones, where there's a big fuss over the difference between a broad sword and a falchion, and between scale mail or banded mail. Apparently these kinds of distinctions aren't what the Shadow of Yesterday is all about.

Damage, or "How Much Does My Life Suck?"

For starters, the Shadow of Yesterday makes absolutely no distinction between the suckiness of getting stabbed in the back, and the suckiness of (say) getting a parking ticket. Naturally these events would have different consequences in the imaginary world of the game, but from a purely mechanical point of view they are treated the same way because each reduces your character's ability to influence the story.

This means that your character can be harmed by a sword fight, a practical joke, losing at cards, and so on.

(It clarifies the matter somewhat to think of this as "general harm" rather than "damage," which most gamers have been brainwashed to view strictly as physical injury.)

Weapons

With this in mind, a "weapon" is redefined as anything that can inflict any kind of harm on somebody.

In the Shadow of Yesterday, a weapon's potency is proportional to the narrowness of its domain. A weapon, such as a sword, that inflicts physical harm in all contexts receives a +1 bonus. Alternately, you might have an edict from the king that enables you to sieze property from people: this would be a +1 weapon too, inflicting legal harm.

If the weapon only does harm under particular circumstances,its bonus is +2 instead. There might be an ax, for example, enchanted so that its blade is razor-sharp against the trees of a particular forest, but dull otherwise. Maybe that edict only entitles you to sieze property from those who haven't paid their taxes, or from members of a particular religion.

If the circumstances are very rare, the bonus is +3. So: there might be a spear, infused with the soul of a demon, that hungers to kill one particular person--and against that person it does +3 harm. Maybe that edict only lets you sieze property from criminals with the last name of Sullivan.

Armor

Same deal goes for armor. Basically, if it protects you from a general class of harm (physical, legal, emotional, whatever) under all circumstances, it is +1 protection. If it only handles a general class of harm under particular circumstances, +2. If the protection works under extremely specific circumstances, +3.

An example

Let's say you are the possessor of a magical sword last wielded by Absolon, the sacred God-King of Maldor. This is a bad-ass relic with awesome powers.

• It's a sword, so it does +1 physical damage generally.
• It looks so cool that it gives a +1 bonus to get your way socially.
• It's enchanted to deflect attacks: +1 physical armor.
• Maldorites revere it: it gives you +2 social armor in the Maldorite court
• The sword is a repository of the souls of other kings, who advise you in war. You get a +2 bonus to strategies when in command of the royal army.
• The sword was specifically forged to slay the prophesied Hellbound Usurper: it gives +3 physical damage against this person.

Limits

The rules say: "Your weapon adds to the harm you do to me, up to a maximum level of 6, so that you never automatically win. My armor subtracts from the harm you do to me, down to a minimum level of 1, so that armor never automatically negates all harm." Do you add the weapon first, or subtract the armor first?

Just add and subtract normally. The final outcome can't be more than 6 or less than 1. That is, apply weapons and armour, then limit to the allowed range.