Minimalist weapons (2026)

I've tried this before: rationalizing B/X weapons and giving a few extra options without too much complexity.

I also gave weapons more reasonable prices and weights (encumbrance system to follow).

Now I'm writing my "OSR Minimalist" again and this is what I'm going with.

This is my latest attempt, and I'm quite happy with it. 

Tell me what you think! Did I miss anything?

Melee Weapons

In the case of melee weapons, the damage, price, and weight are determined by size.

 

Size	Damage	Price	Weight
Small (S)	1d4	$3	1/3
Medium (M)	1d6	$5	1
Large (L)	1d8	$10	2
Great (G)	1d10	$20	2

 

Small weapons can be used in the offhand and thrown (20 feet). E.g., dagger, dart, sap.

Medium weapons are used in the main hand and can likewise be thrown (20 feet). E.g., short sword, hand axe, light mace.

Large can be used in one or both hands (+1 damage when used with both). E.g., longsword, dane axe, heavy mace.

Great weapons must use two hands to attack. Two-handed sword (zweihänder, claymore), great axe, lucerne hammer, maul, most polearms, etc.

 To further differentiate weapons, here are some optional traits.

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§  Expensive: double the cost.

§  Quick: if you roll minimum damage, make one immediate free attack against the same target (once per turn).

§  Reach: attack from second row (5' extra).

§  Charge: double damage on a charge or when set against one.

Here are some common weapons:

§  Axes, maces (M, L, G). +1 to hit shields, heavy armor, hard or brittle targets. Axes also get +1 against wood and maces +1 against stone.

§  Brass knuckles (S, $1). 1d2, quick.

§  Clubs (S, $1). No special features.

§  Daggers (S). Expensive, quick.

§  Flails (M, L, G). +1 to hit shields or heavy armor, +2 if both, -1 if none.

§  Javelins (S). Thrown 30', weight ½.

§  Kick (S). 1d2; on a natural 1, risk falling prone.

§  Pole weapons (L, G). Expensive, reach, charge, plus same effect as axe and mace.

§  Punch (S). 1d2−1, quick.

§  Quarterstaffs (L, $3, 1d4 damage). Reach or quick (choose when attack).

§  Spears (M, L, G). Reach, charge.

§  Swords (M, L, G). Expensive, quick.

§  Warhammers and warpicks (M, L, G). +2 to hit heavy armor, hard or brittle targets, -1 against unarmored and soft targets.

G weapons: +1 damage vs. larger-than-human foes, −1 to hit smaller-than-human ones. Swords and spears get +1 damage if M, +2 if L, +3 if G. 

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Ranged Weapons

 All ranged weapons require ammunition and two hands to operate. 

Weapon	Damage	Price	Weight	Range	Notes
Sling	1d4	$2	1/3	40'	-
Short bow	1d6	$20	1	60'	-
Long bow	1d6	$30	2	70'	-
Crossbow	1d6	$40	2	80'	Slow

• Slow: spend one round reloading between shots. 

Ammunition costs:

• Arrows or bolts — 20 for $5, weight 1.
• Sling bullets — 30 for $1, weight 1.

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Note: I may or may not combine this with an optional critical hit checklist (and fumbles) to give weapons even more distinctions.

Also, let me know: would a list of ~24 weapons be easier to grasp than this "choose the size of your weapon" scheme? Or something else (e.g., list of weapons and sizes versus separate list of traits...)

I'm leaning towards leaving lhe list of simple weapons in the minimalist version and adding the full list as separate and optional.

Example (unfinished):

#	Weapon	Size	Damage	Price	Weight	Traits
1	Punch	S	1d2−1	—	—	Quick
2	Kick	S	1d2	—	—	On natural 1, risk falling prone
3	Brass knuckles	S	1d2	$1	0	Quick
4	Dagger	S	1d4	$6	1	Expensive, quick, thrown 30'
5	Club	S	1d4	$1	1	—
6	Javelin	S	1d4	$3	½	Thrown 30'
7	Axe, mace	M	1d6	$5	1	+1 to hit shields, heavy armor, hard or brittle targets
8	Flail	M	1d6	$5	1	+1 vs shields or heavy armor, +2 if both, −1 if neither
9	Spear	M	1d6	$5	1	Reach
10	Sword	M	1d6	$10	1	Expensive, quick
11	Warhammer, warpick	M	1d6	$5	1	+2 to hit heavy armor, hard or brittle targets; −1 vs unarmored
12	Axe, mace	L	1d8	$10	2	+1 to hit shields, heavy armor, hard or brittle targets
13	Flail	L	1d8	$10	2	+1 vs shields or heavy armor, +2 if both, −1 if neither
14	Quarterstaff	L	1d4	$3	2	Reach or quick (choose when attacking)
15	Spear	L	1d8	$10	2	Reach
16	Sword	L	1d8	$20	2	Expensive, quick
17	Warhammer, warpick	L	1d6	$10	2	+2 to hit heavy armor, hard or brittle targets; −1 vs unarmored
18	Axe, mace	G	1d10	$20	2	+1 to hit shields, heavy armor, hard or brittle targets
19	Flail	G	1d10	$20	2	+1 vs shields or heavy armor, +2 if both, −1 if neither
20	Pole weapon	L	1d8	$20	2	Expensive, reach, +1 to hit shields, heavy armor, hard or brittle targets
21	Pole weapon	G	1d10	$40	2	Expensive, reach, +1 to hit shields, heavy armor, hard or brittle targets
22	Spear	G	1d10	$20	2	Reach, disadvantage within 5'
23	Sword	G	1d10	$40	2	Expensive, quick
24	Warhammer, warpick	G	1d10	$20	2	+2 to hit heavy armor, hard or brittle targets; −1 vs unarmored

Mass combat: broken units

I had a brief mass combat idea that solved most of the issues I had with PCs fighting a few dozen goblins at once.

This assumes there are only a few (say, one to ten) fighters in one side, and several (say, ten to a hundred) in the other.

We already have the usual combat rules for smaller combats, when there is fewer than a dozen foes on either side.

In addition, if you have 60 knights against 150 orcs, you can just treat it almost like a fight of 6 knights against 15 orcs, adapting as needed.

But when you mix everything together, you might have a small issue - still easily fixable.

Say you have four individual PCs, plus 60 knights against 150 orcs. Ten orcs can attack ten knights with a single roll (treat this as one or against one knight); the knights either die or don't.

Ten orcs can attack a single PC instead, with a +10 bonus.

The problem is if the PCs attack a group of ten orcs. Usually, they can only kill one or two (which might break morale and thus the whole unit, but that is another matter). Let's say they are reduced to nine orcs.

Now they can attack the PCs with a +9 instead of +10 bonus—all very intuitive.

But what if nine orcs decide to attack ten knights?

Simply give them a -1 bonus due to the difference between nine and ten, and give the knights a +1 bonus when attacking them.

But let's say we get into a more difficult situation: there are just four orcs, fighting to the death, against ten knights in plate.

They'd attack with -6, making a hit impossible. Instead, they could choose to make an attack against a single knight, now with +4. Now it is more likely that they'd kill at least one before being wiped out by the remaining knights.

Another option, maybe even easier, is saying that the 4 orcs can attack 4 knights - no bonuses or penalties. Treat this as one orc attacking one knight. Either the ten knights are reduced to six, or remain unharmed [this works somewhat similarly to the game Risk].

Conversely, if 7 knights attack 3 orcs, treat this as a single knight, attacking a single orc, with a +4 bonus. If that single orc is slain, it means all three orcs were defeated.

This system looks a bit complicated until I organize it, but it is very intuitive to me, and the results are not terribly far from the what you'd get but making each single attack separately - or at least close enough for my taste.

My goal, here, is never having to keep track of "minor NPC" HP, and never needing another set of rules - just roll 1d20, consider THAC0 and AC, use damage as written, etc. No need to convert to d6s, roll handfuls of d20s, and so on.

[BTW, if you own handfuls of d20 and d10s, you can easily use them as pawns, altering the digits as the units dwindle - for example, a d20 on 7 means 7 knights, and a d10 on 3 means 3 orcs. But you can also use any chips or counters, including the ones from Risk].

Now I want to playtest this. Looks promising.

Brief mass combat idea

Here is a brief mass combat idea meant for old school D&D or OSR games. I'm using ascending AC in my examples because that's what I use in my games.

Here is the idea:

10 1st level fighters count as a single fighter with a +10 attack bonus until the end of the round.

They attack as one. They deal one die of damage (say, 1d8 if they're using swords).

They add one point of damage for each point over the AC (if using ascending AC).

By Dean Spencer

Let's say 10 bandits are attacking your 5th-level  PC, who has AC 17. They roll 9. Adding a +10 bonus, this means 19, two points more than needed to hit. They deal 1d8+2 damage.

The best part about this idea is how it vastly simplifies things.

If you decide only 4 or 6 fighters can attack the PC at a time, just reduce the bonus to +4 or +6.

If the PC slays a couple of bandits, reduce the bonus to +8. And so on.

In some cases, you can just add up all HD. If your PC is attacked by a 3rd level fighter and 3 bandits, they can make one single attack with +6.

It also makes goblins, etc., dangerous though all levels. If your PC in magical plate and shield gets attacked by ten goblins, it is VERY LIKELY that ate least one of them will get a good stab!

This will probably be useful when PCs have multiple henchmen too. One roll, period.

Is this similar to actually rolling each attack individually? Well, it varies a lot depending on AC, number of foes, etc. Apparently, the bigger the group, the smaller the damage each individual adds (which might be explained by fewer people being able to attack at the same time). 

Let's try with six goblins attacking a fighter in plate [AC 16], using B/X (or OSE) rules. The usual damage per round (DPR) would be around 5.25. With my proposed rule, it would be about 4.4. 

If the fighter is unarmored, DPR is also similar (11.55 versus 9.78, more or less). Not bad.

And if the fighter has plate, armor, and some magic bonus to AC? Let's say AC 20? An extreme case, but... Then damage doubles from about 1.05 to 2.28. So the rule works as intended!

(These numbers were calculated with the help of AI... let me know if they're wrong!)

I probably wouldn't use such a rule if you're fighting a couple of giants, for example; just for low-level foes. Likewise, allowing 15 goblins to attack you at once sounds unwieldy; I'd keep the limit at 10 for now, and you ever fight 20 goblins at once they cannot attack you as a single unit (treat them as two groups).

I probably COULD use this idea for huge mass battles, just adding a few zeroes when needed.

Say, a force of 90 knights clash with 50 enemy knights. The 90 knights attack with a +9 bonus, etc. They deal 1d8 damage (or whatever) plus the margin of success. Then just multiply damage (or casualties) per 10, and reduce the opposing force equally.

I haven't played-tested this. But I have a good feeling about it...

Additional reading:

https://methodsetmadness.blogspot.com/2023/02/the-hd-game.html

More glancing blows (and near-saves)

 A quick rule for any D&D game. I'm certainly not the first one to suggest the "half damage" part.

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Glancing blows

When you roll the exact number needed to hit the target's AC, this is a glancing blow.

You damage is halved.

If the target has more than 1 HP before the hit, the glancing blow can reduce it to 1 HP, but no less.

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This is the gist of it, but we could change the specifics. 

Instead of half damage, for example, I might do "one third of your maximum damage" to save myself a roll (and further differentiate 1d6+1 from 1d8 damage). 

Likewise, the "1 HP" part probably needs a few exceptions, but it would be fun if even a peasant has a 5% chance to survive being hit by a powerful monster and live to tell the tale (even if unconscious, maimed, etc.  -the idea is that a glancing blow doesn't kill).

You could extend the same reasoning to saving throws. This is somewhat similar to what I've been doing in my games. When the MU casts an 8d6 fireball, I make a roll even if the target is a group of goblins, allowing a natural 20 to save some of them. I might call this rule "there is always a save".

D&D 4e had minions rules that worked in a similar way: "minions" had only 1 HP but wouldn't be killed if they made a successful save. 

I think my version feels a bit less artificial. No goblin should resist TWO 8d6 fireballs! Also, REDUCING a foe to 1 HP is a great opportunity of surrender, retreat, parlay, etc.

I also like making glancing blows a common concept so my players can finally accept I'll eventually tell them the monster's AC, so they might as well stop asking if they hit!

Anyway, for now this is just a random thought.

Weapons vs. monster

We discussed weapon versus armor in several posts. I think it is an interesting subject, but I'm still not sure it is worth the effort.

It probably works better when you're running troops of humanoids against each other, a la Chainmail. But what about dragons and ogres? AD&D suggests the table doesn't apply to them.

But, arguably, knowing if you foe is a dragon or ogre is more relevant than chain versus plate.

So maybe we should do "weapon vs. monster" tables instead of "weapon vs. armor"?

Of course, we already have something like that at least since AD&D. I don't remember if if it is from some  OD&D supplement (let me know!), but even in Chainmail the weapon versus armor table has a couple of columns for horses (and also different hit probabilities against ogres, dragons, etc.).

Could we create a minimalist version for B/X and other OSR games?

I think it would be a good idea. Let's see. Instead of specific monsters, I like to think of monster types.

- Giants are resistant to small weapons, but more vulnerable to large weapons, especially swords and polearms. Same for oozes. (although I think giants also deserve an HP boost for that). The downside is that David vs. Goliath becomes harder.

- Golems are resistant to cutting and piercing weapons, plus weapons made of wood. You need a mace of pick for that. Of course, a golem made of straw is weak against cutting and strong against bludgeoning.

- Plant creatures and wood golems are more vulnerable against cutting weapons, especially axes.

- Arrows and daggers are weak against ALL these creatures (you're unlikely to reach their vitals), plus undead, but maybe daggers are good against unarmored and defenseless humanoids. Would give thieves a reason to use them over longswords.

- Blunt weapons are good against skeletal undead and similarly brittle creatures.

- Lycanthropes require silver weapons. Demons, fey and golems have magic resistance. Elementals resist most weapons and certain elements, and so on. Swarms resist all weapons.

Dragons and other monsters are treated according to size.

How to enforce that? I think a simple -1 to +2 to both attack and damage will suffice. Anymore than that would probably be a headache.

If we only had giants and oozes to deal with, I'd give them some damage resistance - maybe 4 points? - but allow a weapon to roll two dice instead of one. So a dagger would have a hard time but a 2h-sword would deal more damage than usual (2d10-4).

And then we'd have to consider giants in armor... sigh. Maybe doing a simple version is not so simple after all. But it might be worth the effort, at least to different weapons and make the monsters more... tangible?

Your D&D character doesn't have scars, and I think this is a problem

Your D&D character doesn't have scars, and I think this is a problem.

I'm not talking about your level 1 PC - before adventuring starts, his scars are just cosmetic. 

Some RPG systems have mechanics for hindrances/disadvantages, and that is cool too, but I don't think it is strictly necessary. What happens BEFORE the game begins is not as important ad the actual game.

I'm not talking about healing spells either, although maybe they ARE part of the problem.

I'm talking about your high-level warrior, who has been trough dozens of battles, got stabbed, bitten, knocked out, and almost died several times.

He might have acquired many treasures, gained famed and riches, defeated several monsters, he might even rule a castle, but, by the way it looks, there was no simply no cost.

I'm not talking about appearance only.

Instead, I'm wondering if there should be a place in your character's sheet for old wounds. Maybe a missing finger, or even an eye (that will give you disadvantage when shooting bows). Maybe -1 Charisma from a hideous facial scar, or -1 Dexterity due to a ruined knee.

They don't need to be permanent, but some might be.

It doesn't need to happen often, nor does it need to happen to every PC.

I guess what I want is to at least have a possibility of actual wounds after dozens of dangerous battles.

These might not be to everyone's tastes. 

As doesn't fit every genre. You could even say that Conan, Elric and John Carter rarely get significantly wounded. Add healing magic to it, and you have every reason to believe your setting is full of veteran warriors without a single old wound.

But I really feel this makes the game less interesting. 

Scars and wounds give PCs history, even more than their stats and weapons do.

You are unlikely to remember how you got to level 5 and even where you got that +2 sword, since you get so many.

But you'll probably remember why, where and how you lost a finger...

Anyway, getting this to work in the table isn't easy. Nobody likes playing a severely wounded PC that doesn't heal.

Critical hits come to mind, but this is not an ideal solution; it is likely that they'll cause TOO MANY WOUNDS because PCs fight so often. Fighting and horde of goblins will surely cause several critical hits, for example, even for the experienced fighter, and even heavy armor will not protect you from crits if they are caused by a natural 20.

Wounds probably need to come from being reduced to zero HP (the 1e DMG subtly suggests this as an alternative to death). 

This way, your wounds will not be as terrible - they will remind you of that time when your nearly escaped death!

Additional reading:

https://methodsetmadness.blogspot.com/2024/12/nothing-to-lose-but-their-lives-stakes.html

NOTE: there is a California Wildfire Relief Bundle on DTRPG. It has lots of Savage Worlds (including Savage Worlds Adventure Edition) and a couple of OSR games. "By This Axe I Hack!" and "There and Hack Again" are the most interesting to me.

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Single attack/damage roll (kubular), but divided in half

I think I discussed that idea at the time, but I didn't write down this exact implementation. Read that post before this one! This method has several advantages over the usual D&D method.

Here is the deal: no more damage rolls.

Just roll 1d20 plus modifiers and subtract AC, then divide by two: this is the total damage (minimum 1).

Modifiers include attack bonus and weapon rating (WR).

WR usually goes from -3 (unarmed) to +3 (heavy 2H-weapon).

A dagger has +0 WR; other weapon are easy to figure out (d6, d8 and d10 become +1, +2, +3).

Improvised weapons, gauntlets, etc, have a WR of -1 or -2.

Lets assume ascending unarmored AC 11 (like BFRPG).

A dagger hit deals an average of 3 damage against unarmored targets, a bit over the original (nice!).

A 2H-sword, OTOH, deals 3.77 damage on a hit, but hits more often than in the original BFRPG; the DPR (damage per round) is about 2.45, a bit HIGHER than the usual 2.25.

What about heavy armor? Say, Plate mail is AC 17 in BFRPG. 

To hurt someone in plate with bare hands, you need a natural 20 (realistically, you'd be more likely to hurt your hand... add some grappling rules to your game!).

A dagger will only deal 1.5 points of damage. 

A 2H sword deals an average of 2.5 damage (originally 4.5), but again the DPR is 0.8, not far form the original (0.9).

I'd definitely combine it with some "armor defeating" rules for maximum effect. E.g., cutting weapons deal 1 point of additional damage if they hit, maces get +2 to-hit against chain or heavier, axes are +1 against everybody, etc.

(Yet another) critical hit system for B/X, AD&D etc.

 It is quite simple:

A) Natural 20 means maximum damage.

B) Beat AC by 10 or more means double damage.

This has several advantages.

"A" gives you a quick, optimal result that is still within the expected boundaries. You can deal maximum damage at any time, but a natural 20 guarantees it. No "whiff factor". The average damage is not significantly impacted.

And "B" gives you:

- The fighter to get a small boost in damage, especially against weak foes, which is good.

- Armor becomes more important - going unarmored is now a terrible idea.

- The thief gains more damage with backstabbing. This is good for B/X but maybe unnecessary for AD&D. OTOH the B/X thief becomes a bit more frail due to light armor and low HP.

Both give more importance to strength bonuses and magic weapons, and even make two-handed 1d10 weapons a bit stronger (although a shield also becomes more important).

But what if both happen at the same time?

There are several solutions.

- Double maximum damage. This would occasionally allow a B/X fighter that usually deals 1d8+2 damage to deal 20 damage with a single blow.

- Double damage, but ONE of the dice is automatically maximum damage (i.e., 1d8+3 becomes 8+1d8+6). I like this solution because the maximum damage is still impressive, but the average is a bit lower.

- Double damage plus another attack. I like this one because it gives the fighter some cleaving.

A caveat: monsters will get more dangerous too.

This is not a HUGE problem IMO; I like dangerous monsters, and with multiple attacks monsters are likely to spread the damage a bit. But it is something to keep in mind.

Some MMA-Melee reflections

I was talking about "medieval MMA" on twitter the other day and another user (@D20Gary) made a good point about how every attack "hits", and we could just roll damage instead of "to-hit" like Cairn does.

Gary makes a good point - in melee, almost every attack "hits" - even if only "hits" shield, armor or weapon. 

It is very rare that someone would hit air.

However, I disagree with the solution (and don't use a Cairn-like system), because not every attack DAMAGES.

Look at the video below, for example. Several attacks "hit" armor but not necessarily HURT.

It is often said that a "miss" in D&D could be a glancing/weak hit.

Although practice might vary from table to table, it is obvious that it must be so - just think about the numbers and what AC means.

E.g.: say your fighter "hits" by rolling 8 or more against an unarmored foe.

If the foe is using plate, a 8 or more obviously mean you still "hit" the target, but with not enough skill to bypass/defeat armor.

This can be seen in the video, over and over.

Another problem is that each fight like the video takes dozens of "hits" or more to  finish. 

Even with an average of 1d6 damage per round, every fighter would need 60+ HP, leading to HP bloat.

(This could be avoided by adjusting damage - apparently, Cairn does this by subtracting armor from damage, which is good).

So, even in the context of the MMA-melee video, a D&D-like system seems to make more sense - decent level fighters constantly "hit" but not always "damage".

HOWEVER...

I agree that needing TWO rolls for attack AND damage is redundant, ESPECIALLY if you consider "misses" are not necessarily MISSING the target.

The hit/miss binary is just too "low resolution" - doesn't measure quality or even separate "misses" from actual misses (i.e., "hitting air").

My favorite solution would involved a single d20 roll with some nuance. This has been attempted in several ways in here (see links below), and by many before me.

Anyway.

On a related topic.

What we said above is true for "MMA melee", but not so for actual MMA or boxing - it is not unusualk to "hit air". Same for shooting bows, etc.

Now think of the various forms of combat:

- Unarmed, which includes striking AND grappling.

- Melee with armor. 

- Melee without armor (e.g., fencing). 

- Bows. 

- Firearms.  

These are so incredibly DIFFERENT in reality that a single system is unlikely to work well for ALL types.

A dagger fight ends in minutes without armor, but can last HOURS in plate.

Add a knife to a boxing (or wrestling) fight and it changes EVERYTHING.

Just change the surroundings - from forests to tight dungeons - and the whole dynamic is different.

Lethality, speed, distance, % of hits landed, lasting wounds, etc. are just too diverse.

So, you either have SEVERAL combat systems or accept that these things will be mostly abstract.

It is difficult (maybe impossible) to have a system that is both realistic AND simple - not to mention FUN to use at the table.

Still, we keep trying...

Additional reading:

https://methodsetmadness.blogspot.com/2024/01/single-attackdamage-roll.html

https://methodsetmadness.blogspot.com/2024/02/hitting-armor-in-d-glancing-blows.html

https://methodsetmadness.blogspot.com/2023/06/minimum-combat-detail-deadly-daggers.html

https://bxblackrazor.blogspot.com/2024/07/d-combat.html

10:1 combat (B/X, Chainmail, and OD&D)

There are innumerable ways to do mass combat in D&D (I even tried to write my own). 

In old school editions, however, I am not sure it is even necessary to have a mass combat system.

On the contrary, I've been thinking a separate mass combat system might become a problem.

Take Chainmail, for example. Many people that play OD&D or AD&D like the idea of using CM for mass battlers, but I find this a bad idea.

In Chainmail, the mace is FIVE TIMES better than a regular sword against AC 2. In AD&D, since you can hit even negative AC with a 20, the mace is only slightly better than a sword.

This is the first thing that comes to mind, but there are many other differences - IIRC, a 4th-level fighter is much stronger in CM, for example, and using 2d6 will necessarily produce different results from a  d20.

My problem with this is that switching systems like that changes the assumptions about the game, to the point of changing the results of a fight depending oh the system you're using.

But what if you just use the same system with a different scale?

For example, say 100 knights are battling 150 berserkers. You could just run 10 knight "units" against 15 berserkers "units", as if they were individuals, and assume the results would be similar. 

I.e., a "10:1 scale"; one knight represents 10.

The rules would be exactly the same... with a few exceptions.

Morale

An unit tests morale upon losing one HP and again when losing half HP.

Notice that usually morale is checked when one combatant dies. If taken literally, this would indicate hat an army of 100 might flee is attacked by an army of 100 inflicting a single causality. I dislike that, and I only check morale when 10% of an army/unit is lost.

Interaction between scales

What happens when a unit of 10 knights attacks an ogre or even an exceptional PC?

Reverting back to the usual system is not a bad idea - it is easy enough to roll 10d20, etc.

Although I do think you should decide beforehand how many people can attack a single target at once (I like four, maybe twice as much for spears).

Likewise, the number of units attacking other units is limited and depends on geography.

When combat is resolved (because the ogre is slain or inflicts a causality and the knights fail a morale test), you can stay in 10:1 or 1:1 scale as appropriate.

Other scales/my experiences with mass battles

Of course, you can use other scales as appropriate. You could use 5:1, 100:1 or 1,000:1... The idea is finding a number of units that makes you comfortable. 

I have little experience running mass battles like that. But my PCs recently fought about 50 goblins in two or three waves, with the help of half a dozen NPCs, and it went very well. 

I once ran a 5e combat against 100 skeletons or so, which was also very easy as they came in groups of 4-5 thru the windows and the fighters would only miss them on natural 1s.

I think it would be hard to run more than 10 or 20 units at once, but within that limit I'd want to have as many unis as possible.

In addition, I'd have to consider unit types; if I have 1000 identical knights, I can use 100:1, but if I also had 50 archers, I'd definitely prefer 50:1. 

In any case, you can "zoom" back and forth as needed.

Well, for now, this is just brainstorming. Let's see if I can out it in practice.

The importance of cleaving mooks

I recently wrote a couple of posts about how B/X Fighters are too weak and how to fix them.

There is one thing I want to elaborate further: "cleaving" (or sweep attacks, etc.). 

As it often happens, there is a great post in Delta's blog about the subject, which covers most of the topic.

This is an ability the fighter had in OD&D and AD&D, that is missing from B/X. Here is how OSRIC describes it:

"Fighting the Unskilled: When the fighter is attacking creatures with less than a full hit die (i.e. less than 1d8 hit points), the fighter receives one attack for each of his or her levels of experience, e.g. a 4th level fighter attacking goblins would receive 4 attacks per round."

Delta's describes the importance of this rule when fighting hundreds of goblins. Notice that the number appearing for goblins is:

- In B/X, 2d4 in the dungeon and 6d10 in the wilderness. 

- In AD&D, it is 40d10.

This rule is useful not only to give the (very) high level fighter a chance against a goblin horde, but also to balance the power of fireballs (and similar spells) somewhat.

There is also a narrative importance to this rule that is worth mentioning.

In fiction, the "main villains" are often surrounded by low level "mooks" that must be defeated first by the protagonist. In RPGs, I've seem PCs ignore all mooks over and over again to attack the villain directly, as if the main villain was all that mattered. 

Which, fair enough, can be a good tactic, especially in the absence of "opportunity attacks" and the like.

However, it makes me wonder if the reason is not the lack of a cleaving rules, which would often encourage the fighter to make 10 attacks against the goblins instead of going directly for the goblin king/captain - which is a bit less likely to die in a single blow and usually deals significantly less damage than 10 goblins combined.

If you decide that the death of a leader will cause some penalty to morale, this introduces and interesting tactical choice.

Fighting hordes of mooks at once is also something that Appendix N characters like Conan and Elric can do.

In addition, let's remind that hacking down hordes of ores feels awesome for the fighter.

Amazing art by Dean Spencer.

My main issue with "Fighting the Unskilled" is that it lacks nuance. A 10th-level fighters has 10 attacks against goblins, but only one or two against orcs. 

Notice that orcs also appear in greater numbers in AD&D than B/X, but are not subject to these extra attacks.

Another difficulty is how these "extra attacks" combine with multiple attacks. If a 7th level fighter has 3/2 attacks, how many attacks does he get against goblins? Seven? 8/7? 

Weapon proficiency confuses things further.

This is why I like the "cleave" solution, from 3e, as explained in Delta's blog:

3E D&D

CLEAVE  [General] You can follow through with powerful blows. Prerequisites: Str 13+, Power Attack. Benefit: If you deal a creature enough damage to make it drop (typically by dropping it to below 0 hit points, killing it, etc.), you get an immediate, extra melee attack against another creature in the immediate vicinity... (PHB p. 80)

GREAT CLEAVE  [General]
You can wield a melee weapon with such power that you can strike multiple times when you fell your foes. Prerequisites: Str 13+, Power Attack, Cleave, base attack bonus +4 or higher. Benefit: As Cleave, except that you have no limit to the number of times you can use it per round. (PHB p. 82)

3E D&D introduced the concept of "Feats": special powers that may be chosen as characters advance in level. Fighters get additional, bonus Feats (more than any other class), and the two listed above are on their Bonus Feat applicable list. That said, not every Fighter gets the power; they must make a deliberate choice to pick up the ability. At the earliest, a Fighter might have Cleave at 1st level, and Great Cleave by (you guessed it) 4th level.

Most of us interpret this as a reworking of the rule from earlier editions; if a Fighter (with the Feat) battles very weak creatures, then they're likely to get a chain of attacks that puts many of them down. And many of us prefer the continuity of this mechanic -- unlike in 1E, where there's a huge quantum collapse between fighting "up-to-7-hp" creatures vs. "up-to-8-hp" creatures, the benefit here will more smoothly be usable against 2 HD or 3 HD creatures, just less frequently.

(Of course, I added similar feats to Old School Feats and I use them in my games.)

I'll add that this kind of cleave works smoothly with multiple attacks, magic weapons, weapon specialties, etc: the higher your attack and damage, the higher the chance to use this.

[One small aside: one thing I haven't considered in this post or the one before this is the 5e cleave method of "damage overflow": if you reduce an enemy to 0 HP, any excess damage is dealt to a nearby foe of same AC or lower. This is also a very interesting solution because it is simple, fast as smooth, while it also gives meaning to high damage rolls against goblins, etc.]

In short, if I were to add ONE single ability to B/X fighters, it would be this "great cleave". 

I do not think it would be enough, mind you - I still think they deserve extra attack to improve damage output against solo monsters  - but it would be a great start.