Combat systems of OD&D and Chainmail

08 Nov, 2026

Contents

• Introduction
• Practical Application
• Armor & Weapons
  • Troop Type to Armor Class conversion
  • Troop Type to Weapon Class conversion
  • Bonuses

Introduction ↩

Generally, you have about five combat systems available when running OD&D¹ with Chainmail:²

• Troop Type System
• Man-to-Man Combat
• Jousting
• Fantasy Combat
• Alternative Combat System (ACS)

📝 NOTE: Additional combat systems appear in later supplements: Alternate Combat & Hit Dice System from Greyhawk³ (expanding ACS), Psionic Combat from Eldritch Wizardry,⁴ and entirely new mass-combat rules from Swords & Spells,⁵ but these will not be covered here.

Troop Type System ↩

The main combat mechanics of Chainmail's large-scale (1:20 or 1:10) combat are resolved by rolling several six-sided dice according to the "Combat Tables" (Appendix A, Chainmail, p.40), cross-referencing the attacking vs. defending troop type. E.g., three Medium Horse figures attacking a unit of Light Foot would roll six dice (2 per figure), killing an enemy figure for every roll of 5 or 6.

Man-to-Man-Combat ↩

Additional rules for the small-scale (1:1) battles in Chainmail, resolved by rolling 2d6 according to the "Man-to-Man Melee Table" or "Individual Fires With Missiles" (Appendix B, Chainmail, p.41), cross-referencing the attacker's weapon vs. the defender's armor.

Jousting ↩

An addition to the Man-to-Man rules, this concerns "Knights in 'friendly' combat," using the "Jousting Matrix" (Appendix C, Chainmail, p.42). In the OD&D aspect, this will mostly be used for tournaments and jousting matches with the castle occupants, as described in the "Castles" section (The Wilderness, Vol.III, p.15).

Fantasy Combat ↩

Besides giving Troop Type statistics for various fantasy creatures with the "Fantasy Reference Table" (Appendix D, Chainmail, p.43), the "Fantasy Supplement" of Chainmail brings forth a new set of rules to resolve the combat between more powerful creatures, such as Heroes, Wizards, Trolls, Dragons, etc. (13 categories total), rolling 2d6 on the "Fantasy Combat Table" (Appendix E, Chainmail, p.44).

Alternative Combat System ↩

OD&D provides a new d20-based system based on the character's level (or monster's Hit Dice) vs. the Armor Class of the target (same as in the Man-to-Man tables, from 9 (unarmored) to 2 (plate & shield)), which was later adopted as the main combat mechanic in the later editions of the game (starting as early as Supplement I: Greyhawk³).

Practical Application ↩

During the course of play, you will use all of the above-mentioned systems, selecting the most suitable one for the situation at hand. This is explained more clearly in the "Draft version"⁶ of OD&D, in sections that sadly didn't make it to the release (p.22):

Men vs. Men: If there are small numbers fighting it will be most interesting to use the Man-to-Man Melee Table. If large numbers are fighting the Combat Tables based on a troop ratio of 1:20 should be used.

Men vs. Fantasy Figures: It is suggested that the 1:20 Combat Tables be used, with men scoring 1 hit point when they hit and fantasy figures scoring hits equal to a die roll (1-6). Of course, some fantasy figures cannot be hit by normal men, and no hit points will be scored against them. (See the Fantasy vs. Fantasy section below.)

Fantasy vs. Fantasy: Because of the vast number of fantastic creatures and levels of men, a matrix to show hits is totally impractical (we know because we tried, but with 70 or more categories it became too unwieldy to handle) We therefor recommend that a system utilizing a 20-sided die (incriments of 5%) be adopted.

To summarize it all, here's the basic practical guideline:

• Large-scale combat: (1:20 or 1:10):
  • Men or Fantasy figures vs. Men: Troop Type System with each successful hit removing 1 figure;
  • Men vs. Fantasy figures: Troop Type System with simultaneous hits equal in number to the target's HD required to remove 1 figure.
• Small-scale combat: (1:1):
  • Men vs. Men: Troop Type System or Man-to-Man Combat with each successful hit dealing d6 damage;
  • Jousting: Jousting system;
  • Men vs. Fantasy figures: Troop Type System or Alternative Combat System with each successful hit dealing 1 hp of damage;
  • Fantasy figures vs. Men: Troop Type System or Alternative Combat System, doing one attack as a man-type per HD (or according to the "Fighting Capability" stated in class tables), with any bonuses applying to only one of the attacks, i.e. a Troll attacks six times, once with a +3 bonus (OD&D, Vol.II, p.5);
  • Fantasy vs. Fantasy: Fantasy Combat System or Alternative Combat System, doing a single attack per round.

Here, "Men" are those without a "Fighting Capability" rating and generally having less than 4 HD, such as "kobolds, goblins, dwarves, orcs, elves, men, hobgoblins, etc." ("Questions Most Frequently Asked About Dungeons & Dragons Rules", The Strategic Review Vol.1, No.2,⁷ p.3), and "Fantasy figures" are those having the Fantasy Combat rating, and generally having 4 or more HD (including Heroes, Wizards, etc., as per the Fantasy Combat System).

Armor & Weapons ↩

Troop Type to Armor Class conversion ↩

The classification in the Chainmail's "Melees" section (pp.14-15)² provides the following examples for the footmen troop types:

Light Foot: Missile troops, Swiss/Landsknechte, Peasants, Crews

Heavy Foot: Normans, Saxons, Turks, Vikings, Men-at-Arms

Armored Foot: Dismounted Knights. Sergeants, Italian City Levies and Condottiere

This gives us a rough correlation between the Troop Type and Man-to-Man/ACS Armor Class:

📝 NOTE: There are some contradictory examples regarding the exact split between the three types. E.g., "Bandits: Composition of Force" (OD&D, Vol.II, p.6) stats Leather & Shield as Light Foot, but the soldiers in "The Temple of the Frog"⁸ (Blackmoor, p.40) wearing Leather & Shield are considered Heavy Foot and are also "considered to be armed/armored as that of a bandit". My decision to place AC 6 into the "Heavy" category was also supported by the Man-to-Man Melee and Missile tables having the Leather & Shield "to-hit" target generally higher than the "Leather or Padded" (AC 7) category.

For horses, the Man-to-Man system provides two types: Unarmored and Barded. The same list from the "Melees" section provides some examples again:

Light Horse: Magyars, Mongols, Saracens, Spanish, Turks, Hobilars

Medium Horse: Mongols. Norman Knights, Esquires. Saracens. Spanish. Turks, Turcopoles

Heavy Horse: Knights, Reiter, Gendarms

Thus, Light Horse = unarmored rider and horse, Medium Horse = armored rider, unarmored horse,* and Heavy Horse = armored rider and horse.

* Also supported by "Bandits: Composition of Force" (OD&D, Vol.II, p.6).

For missile combat, most of the time you will be using the Man-to-Man's "Individual Fires With Missiles" table, but for the mass combat table, the categories are:

• Light, no shield (AC 9 or 7);
• Heavy OR shield (AC 8, 6, 5, 4);
• Fully armored (AC 3 or better).

Troop Type to Weapon Class conversion ↩

For melee, the weapon categories are generally based on the Weapon Class stated in the "Man-to-Man Melee Table":

• 1 to 2: Light
• 4 to 8: Heavy
• 9 or more: Armored

📝 NOTE: The "Hand Axe" category is stated as Weapon Class 1 in the original, but since there is no Weapon Class 2 weapon at all, I strongly suspect this to be a typo and treat Hand Axe as the Weapon Class 2 weapon.

There would be some exceptions if you expand the list with other weapon types, e.g., clubs, short swords, and staffs being in the Light category despite their higher Weapon Class. (Additional weapon types will be covered in a later post.)

Bonuses ↩

Magic weapon bonus is added to the roll in Man-to-Man or Alternative Combat System, or adds an equal number of dice in the Troop Type system. Similarly, magic armor subtracts its bonus from the attacks vs. the wearer or from the number of dice rolled against him (OD&D, Vol.II, p.30).

Men-types wielding magical weapons would be able to score full damage plus weapon bonus against Fantasy figures instead of 1 point of damage (or no damage at all), as they do normally (see "Wights", OD&D, Vol.II, p.9).

There is no bonus for High Strength (13-18) for Fighters until Supplement I: Greyhawk³ (p.7), except the note of Strength aiding "in opening traps and so on" (OD&D, Vol.I, pp.10-11). If you want to give the Fighters an edge, I wouldn't suggest granting them anything more than a +1 to-hit bonus for High Strength applied to a single attack, just like the HD Bonus of the monsters.

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