@mcv An ancient post for you about ORE probability: https://asteroid.divnull.com/2008/01/chance-of-reign.html
Nice to see MathJax used, but on mobile, those two formulae get squished together. Separating them might help.
But to be honest, the treatment of exact chances of certain combinations of sets is less interesting to me than issues like blows to the head being harder to parry, and therefore easier to make, than blows to the hands and feet.
My brief stint practicing HEMA taught me the exact opposite: hands and feet are vulnerable (or at least the sword hand and the forward placed foot), whereas head and torso tend to be surrounded by shield and sword to parry them, not to mention having eyes well positioned to see the blow coming.
Making a result of 10 hit the head sounds logical at first, because rolling 10 sounds harder than rolling 1, but that's only true when you need to roll higher. For exact matches, 1 or 10 makes no difference, except that the 10 is harder to parry. So my guess would be that Reign combat tends to see more head hits than leg hits, especially between skilled opponents who know how to parry.
Is that correct?
@mcv Yes. This is a big reason why many ORE games don’t use hit locations or, at least, don’t tie hit locations to height. We played a few sessions with a tweak that, if an attack succeeded after defenses and such, the hit location was determined by the attacker’s highest waste die (unless some ability allowed a called shot, etc.).
Yeah, that sounds like something I've been considering. Maybe let the attacker even choose which waste die determines the hit location, because it's something you often do have some control over. Maybe you don't want to hit them in the head, for example.
Or skip hit locations entirely.
@mcv As for the layout of the post, it was written before smartphones even existed!