Updating my OD&D House Rules

27 May, 2024

After a couple solo playtests I've been tinkering with my OD&D-ish house rules ahead of a scheduled non-solo test.

General

I broke the main document into a 6-page letter paper rules reference and a digest-sized 'player's handbook' with classes & equipment. I wanted a quicker way to look up rules & procedures, and I'm realizing that for this kind of project (where ultimately I'm not trying to market a brand new system) it makes sense to keep everything as modular as possible and to present the rules as just a GM-screen-type breakdown where all the most important beats are written up for me.

Combat

In my initial solo tests of the combat system, I had a party of 4 to 6 face up against 8-10 1 HD enemies -- I think that's a pretty standard OD&D-style combat encounter, though obviously I need to spend more time with other possible configurations.

My system replaced to-hit rolls with a direct damage roll lookup table that was meant to roughly replicate the average damage of a to-hit roll system. I also have a system for managing HD where hit points are rolled anew with every combat, and wounds only registered when a die is depleted.

The problem is that anyone with 1 HP is essentially a guaranteed kill since almost all attacks do at least 1 damage. I found that this saps a lot of the fun & suspense out of combat.¹

So I considered the following fixes:

• Try to patch my system with one or more of the following:
  • Buff player starting HP to make the 1 HD case less likely (something like the GLOG's flattened HP progression)
  • Lower the damage dice in the matrix
  • Allow some kind of save or dodge roll to avoid damage, or use ITO style saves to avoid death/incapacitation when HP are depleted
  • Shift to something like (d20 + damage die lookup - 20) = damage
• Scrap my system and use one of the following established options:
  • The alternative combat rules (probably as presented in Delving Deeper)
  • Chainmail
  • Chaos Reigns (roll 2d6, if under AC, the value rolled is damage)
• Scrap my system and use one of the following exotic options (cool):
  • Kubular's method (damage = d20+AC+HD-20)
  • Roll 2d6, if under AC the higher die = damage

Weighing these options, I revisited my main design goals:

• Use raw OD&D monster stats, ideally avoiding things like old-AC-to-new-AC conversion tables
• Should be calibrated to the idea that 1 HD represents the combat power of a typical footman
• Should ideally resolve an attack in one roll
• I'd like to use a big matrix, for aesthetic reasons and to allow nonlinearities in armor effectiveness
• I want to preserve my currently-used distinction between 2-handed, 1-handed, and concealable weapons without going any more specific

After tinkering, I came up with the following method in which my silly combat matrix gets to stay: roll 1d12 and the damage die specified in the matrix (according to attacker HD and target AC), and deal damage if the sum > 10.

This was inspired by Traverse Fantasy's post on damage dice as attack bonus. It checks all my desired boxes, and also:

• The chance of one-shotting a 1 HD figure is about the same or slightly lower relative to the standard 'alternative combat system' except when a very high HD figure is attacking
• Going from AC 9 to 8 always reduces the damage die a step, piling on more armor is beneficial but has diminishing returns.
• Dodecahedrons are cool. Most people will probably hate not using a d20 or 2d6, but it's my system suckas!
• 'Roll above 10' is easy to remember

Travel

In my original travel rules I tried to mimic my dungeon crawling rules by allowing characters to take on roles (guide, forager, lookout) and roll a d6 to do things like prevent surprise, not get lost, etc.

I think the basic idea has potential, but it's too convoluted for solo play & the division of labor makes less sense in long & expansive wilderness turns than in a dungeon. And most importantly, Antibor is has 43,000 hexes to explore, so procedural friction should stay really, really low.

• ML provides terrain type of neighboring hexes, players proceed to a new hex, if able.
  • ML rolls encounter die (d6).
    1. Random encounter (d12) 1-6. With inhabitants of closest lair or settlement 7-10. Roll on regional encounter table 11. Completely random monster 12. Dealer's choice
    2. Encounter with hex inhabitants (if any)
    3. Shift weather on hex flower
    4. Navigation check
  • Resolve hex encounters.
    • Roll surprise for each side. 2-in-6 in open & flat, 3-in-6 in hilly or forest, 4-in-6 in jungle, mountains, xenoformed.
    • Encounter distance: 2d6x3" (30 feet) if not surprised, otherwise 1d6x1"
    • Reaction roll (see below)
    • Resolve combat or negotiation
    • ML provides clues to hidden hex features (if any)
  • If end of day, camp and roll nighttime encouner die, otherwise repeat.

#archons-and-armigers #game-design #odnd