Old-School Reduction: Combat Rounds

This is part of a series describing my efforts to apply reductionism to OSE. My aim is to boil down some of the basic rules to something that can be easily transplanted into the more free-form systems I prefer.

Last time I discussed how the AC, HD, AT, TH, and SV stats are used in the context of attack rolls, hit die rolls, and saving throws. Nothing especially ground-breaking, but it helps my thought process to get it all down in writing. Continuing with the "bottom-up" approach, let's examine the concept of combat rounds.

Order out of chaos

Diplomacy breaks down, weapons are drawn, and at last we reach the inevitable "failure state" of the old-school adventure. From the storm of confusion and violence emerges a surreal ballet governed by a basic mechanic: the venerable combat sequence. Of course, D&D combat resembles skirmish warfare about as much as chess resembles the Battle of Agincourt—it is far more "gamist" than "simulationist" (if you'll allow such terms). But, after all, we're talking about a game here, not a historical reenactment.

A "round" is ostensibly 10 seconds of game time, but that's really just an approximation for convenience. Although we say that failed attacks "miss" that doesn't necessarily mean there's no physical contact, only that it had no material effect. Likewise, a "hit" may represent a single strike or the cumulative effect of a series of blows. It's up to the ref to interpret what the die rolls mean in the context of the game's fiction; meanwhile, the same die rolls determine—impartially—who survives the encounter and who does not.

Assumptions

The following might seem obvious to seasoned gamers. Even so, I find it helpful to lay everything out clearly.

• Combatants are divided into 2 or more sides.
• A side may be composed of many members or a single individual. If a group, the members work together toward a common goal (e.g., to defeat the opposing side/s).
• One side may be allied with another (if there are at least 2 others) but they still act independently.
• Each combatant is either engaged (i.e., in melee), unengaged, or out-of-action. When using miniatures, the bases of 2 or more opponents touching indicates that they are engaged in melee, whilst a figure off the playing area is out-of-action.
• Anyone engaged in melee has comparatively limited options as to what they can do during a round.

Analysis

The OSE combat sequence has 5 phases: morale, movement, missile, magic, and melee. Each "side" rolls 1d6 to determine which acts first, with ties acting simultaneously. Special actions, including attempts to disengage from melee, must be declared before the roll. Combatants attacking with "slow" or two-handed weapons act last.

This is already fairly intricate, and optional/alternative sets of rules only add further complexity. Are there ways to simplify/generalise the process without losing too much of the core aesthetic?

Initiative

The most obvious (to me) simplification is to have all combatants act simultaneously every round unless there's an in-game reason why a given side can't do so (e.g., ambushed). Simultaneous action is baked in to the original rules anyway, so this isn't earth-shattering. The players and the ref declare up-front what each combatant does during the round, but anyone can change their mind right up until the dice hit the table.

Critically, though, all hit die rolls occur at the end of the round.

Morale

I was tempted to replace this rule with a free-form mechanic, but it's such a key part of the "old-school" experience that doing so would undermine what I'm trying to achieve here. Thus, the morale check remains more or less unchanged.

The fact that PCs and NPC followers are basically exempt is irritatingly… asymmetrical. I understand the need to preserve player agency, of course, but this feels like an area ripe for tweaking. For now, though, I'll exercise self-control and leave things as they are.

For now. [EDIT: Eh, I couldn't resist.]

Movement

A holdover from wargaming, movement rates are nonetheless pivotal to other core concepts such as weapon ranges, areas of effect, encumbrance, and so forth—they are a necessary evil. For this effort, I'm only interested in encounter movement rates, though others should be trivial to derive. I've abstracted it to a number of "spaces" (notionally 10'×10'), equally usable as inches at the traditional 1:120 scale.

Single-digit movement rates are tempting targets for further hacking… but I'll restrain myself once more.

Procedure

Once combat begins, use the following steps to determine what happens.

1. Morale: If the situation demands a morale check, roll 2d6 for each side affected. Each member with a morale rating (ML) less than the result must surrender (effectively taken out-of-action) or else attempt to flee, if possible.
• A morale check is typically triggered when…
• … the first member of a given side is taken out-of-action.
• … half the members of a given side are taken out-of-action.
• If a given side has a strong, present leader, use its ML for all members of that side.
• The ref may add modifiers up to ±2, based on the circumstances.
• ML12 creatures are exempt: these always fight to the death.
2. Declare: All combatants declare their actions for this round.
• An engaged combatant may either attack another creature in the same space or else try to disengage from the melee…
• … by fleeing at the creature's full movement rate (MV), leaving them open to attacks of opportunity; or…
• … by moving backward at half the creature's movement rate (MV/2, rounded up) into an empty space (i.e. a "fighting withdrawal"); or…
• … by taking the last opponent in the same melee out-of-action.
• An unengaged combatant may do any of the following.
• Move up to to the creature's full movement rate (MV)—including into melee with another combatant, thereby engaging with and attacking that opponent.
• Ready a weapon or other accessible item of equipment.
• Shoot or throw a readied missile weapon at a target within its effective range.
• Reload a readied missile weapon.
• Initiate a special action that will (usually) take effect at step 4 unless interrupted by a successful attack.
• Pass and take no action this turn.
• A combatant who is out-of-action cannot act, obviously.
3. Attack: Make attack rolls, as applicable, in any convenient order.
1. Roll 1d20: 20 always hits, 1 always misses.
2. Add the defender's AC to the roll.
3. Add modifiers as determined by the ref.
4. If the result is greater than or equal to the attacker's TH, the attack hits; otherwise it misses.
• A successful attack delivers a number of "hit points" determined by the attacker's AT and (optionally?) the weapon wielded.
• Keep track of any creature that suffers one or more hits this round—perhaps "tap" its character card (i.e., turn it 90°) or lay its miniature on its side.
4. Special: Special actions initiated in step 2—or the special effects of certain attacks—now take effect. Make any requisite saving throws, as applicable.
1. Roll 1d20.
2. Add modifiers as determined by the ref.
3. If the result is greater than or equal to the creature's SV, the effects are avoided or somehow mitigated (e.g., damage halved). If not, the creature is usually taken out-of-action.
5. Hit dice: Roll hit dice for any creature that suffered harm in step 3 or 4.
1. Keep a running total of all hit points sustained.
2. Roll a number of d6s equal to the number of HD.
3. Sum the values and add the HD modifier.
4. If the result is less than or equal to the running total, the creature is taken out-of-action.
6. Repeat: Repeat steps 1-5 until all remaining opponents have fled or are out-of-action.

Well… that's about as straightforward as I can make things without completely gutting the system. I guess that'll do.

Perhaps next time I'll take the basic adventuring party from a couple posts ago through a fight with… what? A grizzly bear, perhaps? Leave me a comment if you have a better idea.