Dueling Rules for Into the Odd

EDIT 

Re-written and re-posted to remove endorsements of unworthy people.

EDIT 2 

I had a chance to use these rules in a recent game. They really worked! Clever selection of actions allowed one of my players to defeat an opponent who -- stat-wise -- absolutely out-ranked him. The amounts selected for the various bonuses seemed about right. The players remarked afterwards how fun that duel was.

Anyways... 

Recently, I mentioned that I was unhappy with the Into the Odd dueling rules that I made up mid-game. The always awesome Anne @ DIY & Dragons left a comment helpfully pointing me towards a set of OSR dueling rules by the excitingly excellent Emmy Allen @ Cavegirl's Game Stuff. After looking at Emmy's rules -- wow, that's a really good way to have a duel that seems like an event.

And I think I can make them work with Into the Odd rules and stats.

"Cavegirl" Dueling for Into the Odd

(A lot of the text below is straight from Emmy's rules, so writing credit to her.)

• Once the duel has begun (which might be in the midst of a larger fight), the combatants continue to fight turn-by-turn as normal, until the duel ends. The duel might end because one duelist is slain, because a third party interferes, or because one duelist admits defeat or tries to break away from the fight.
• No shields or armor.
• Each duelist effectively has Armor 2 for the duel, representing their ability to parry and block strikes without effort.
• Each turn, each duelist secretly chooses one of the following actions: Push, Parry, or Feint.
• Reveal actions simultaneously.
• Parry beats Push, as the parrying character turns away the obvious attacks of the push. The character who parried gets +2 Armor.
• Push beats Feint, as the aggressive push forward batters through the attempts at finesse. The character who pushed does +5 damage if they "hit" (attack roll exceeds opponent's Armor).
• Feint beats Parry, as the feinting character creates openings to strike past their enemy's guard. The character who feinted gets an attack Bonus equal to the damage die of their weapon, usually d6. (See Electric Bastionland definition of attack "Bonus")
• If both sides Parry, then the duel becomes a defensive stand-off. Both characters get +2 Armor.
• If both sides Push, then they just batter at each other furiously for the round. Both characters do +5 damage if they "hit" (attack roll exceeds opponent's Armor).
• If both sides Feint, then the duel becomes a complex dance of strikes and counters. Both characters get an attack Bonus equal to the damage die of their weapon, usually d6.
• Both sides roll weapon damage and apply damage simultaneously.
• Damage per usual Electric Bastionland rules, including Scars, rolling Strength saves to avoid Critical Damage, etc.
• Usual default Critical Damage result (knocked out of combat, not dead but will die without assistance). The duel ends.

Optional Rules

• Determine each duelist's effective Armor instead by their current Dexterity: 1~5 DEX = Armor 1, 6~15 DEX = Armor 2, 16~20 DEX = Armor 3. This assumes use of typical dueling swords, rapiers, sabres, etc. May want to use Strength if duel is being conducted with sledgehammers, etc.
• If you want to include shields and armor in a duel, base the effective Armor ratings on the relative protection of each duelist. E.g. duelist with Shield and Breastplate versus unarmored duelist = Armor 3 versus Armor 1. (Give at least a little Armor so attacks can still "miss".) Both duelists wearing roughly equal protection? Armor 2 each.
• If you want to speed up the duel, just use each duelist's actual Armor rating based on the equipment they're wearing, i.e. unarmored is Armor 0, breastplate is Armor 1, shield is +1 Armor, etc. Increase the Parry bonus to +3 Armor; decrease the Push bonus to +3 damage.

Should attacks be Impaired if you're fighting left-handed?

Analysis

Emmy's dueling rules have a base of standard D&D combat: roll to see if you hit, roll for damage. The three actions basically do the following: Parry increases the chance your opponent misses you, Push increases how much damage you do (without increasing your chance to hit), and Feint increases your chance to hit (without increasing how much damage you can do). So how do we emulate that in Into the Odd, a system that doesn't have to-hit rolls?

Narratively in ItO, you describe an attack that does damage to Hit Protection (HP) but not to Strength as a "miss". Your HP essentially become a barrier of misses that your opponent has to overcome before they start actually hitting you. So we could leave that as-is. Duelists slowly chip away at their opponent's Hit Protection until they finally start striking real blows. But you know what? Reading Emmy's rules, I think I like the idea that attacks can completely miss -- i.e. do no damage at all. It slows the pace down compared to normal ItO combat, gives more chance for back-and-forth between the duelists, and a slightly better chance of dramatic comebacks.

There is one mechanic in ItO whereby an attack can do no damage at all: Armor. Armor absorbs a number of points of damage equal to its rating. So for example, against an Armor 3 opponent a damage roll of 1, 2 or 3 would do zero damage -- effectively "missing". By proper etiquette, duels are always fought without armor or shield, so we can forget about any actual armor the combatants have, assign them a duel specific Armor rating, and effectively borrow Armor as a to-hit mechanic for our duels.

So now the three actions can have similar benefits in ItO as they do in Emmy's OSR rules. And we'll base the math for their bonuses on the assumption that most duels will be fought with either a one-handed sword -- d6 damage. (Some combatants might have d8 damage noble swords, which provides a nice bonus, but doesn't actually break the math of our bonuses):

• Parry increases Armor, effectively increasing the chance your opponent misses you. We default the Armor rating to 2, which slightly favors a d6 damage roll actually doing damage. We give a +2 Armor bonus to Parry, which pushes the d6 damage roll slightly against doing damage. Flipping from "likely to hit" to "unlikely to hit" seems like a good bonus.
• Push increases damage by +5, but only if the unmodified damage roll exceeds the opponent's Armor rating. This lets us increase the damage without increasing the chance to-hit, just like in Emmy's rules. +5 was chosen because Emmy's rules give a +3 to damage, but we're usually going to lose 2 damage to the opponent's Armor.
• Feint gives a Bonus to attack, which in Electric Bastionland means you roll an additional bonus die alongside your usual damage die and take the higher of the two results. Basically Advantage on the attack. This lets us increase the chance to exceed the opponent's armor (greater chance of a high number) without increasing the maximum damage possible -- just like Emmy's rules. We can't give a Bonus die greater than the regular damage die without increasing potential max damage, so let's set the Bonus to d6. Maybe d8 if you're using a d8 noble weapon.