Mass Battles

I ran a mass battle last week.
Team Bad Wolf was

• 500 gnolls
• 500 wolves
• 40 gnomes (with siege machinery)
• 50 ogres
• 100 werewolves

Team Good Guy was

• 150 guards shooting ranged (crossbowmen)
• 50 horse-mounted crossbowmen (light cavalry)
• 200 guards in leather armor (light militia)
• 100 guards in chainmail with sword and board (heavy militia)
• 50 commoner slingers
• 30 bandits (“hunters”)
• 5 level 3 rangers
• 15 knights (“paladin 5” — I used knights, gave them lay on hands)
• 20 nuns (“cleric 5”, but really commoners with the same lay on hands)

Team Good Guy also had the PCs, so multiple moonbeams and fireballs were had. They knew they could nova because they had advantage of the abbey walls, a 3000-refugee strong work-detail, a week of preparation and a source of drinking water.

Needless to say, the heroes won the day, scattering the wolves before them. They had extremely strong terrain advantages, overall stronger forces, and several spellcasters.
The game play was a lot of fun, but leant on DM fiat more than I’d’ve liked. It was so wide-scale that picturing things became difficult. Spell interactions were tricky, too, especially passive ones; the cleric used Guardian Spirits and I probably let it deal far, far too much damage 🙂

I grouped units by the 50 instead of the 10, and used 100′ hexes but, to keep it all “on map”, kept 1m rounds.
Doing it again, I don’t think that I would group things so coarsely, because it’s just too abstract, but I also don’t think that I’d want to run something this big with all the die rolls.
Even with average damage, wolves trip their targets and get gang up bonuses and I don’t want to roll 20d20 anyway.

The L&L article on mass battles — lost during their site redesign — suggested 10 units to the token, 20′ to the hex, 1m rounds. It also suggests that these deciunits then be grouped in formations, which was something this battle totally missed. I think what I might like to do is roll a single attack for an entire formation which would indicate half of the formation hit. For every 2 by which the formation hit/missed, another half of the remainder hits/misses, to a minimum of another 1 hit/miss until all hit or all miss. Round as seems reasonable.
Example time!
Baddies: a formation of 7-groups-of-10 gnolls led by a gnoll hero-captain
Goodies: a formation of 3-groups-of-10 guards and 2-groups-of-10 archers led by the party cleric and, from the rear, the party wizard.
Because the formation is intended to protect the archers and wizards and is capable of doing so, they have +2 cover against attacks (but everyone has the same cover against them).

The gnolls attack. The 70 gnolls get 7 mass attacks and 7 individual attacks per individual.
The gnolls commit 4 attacks against the guards and 3 attacks against the archers.
First, the guards; if the gnolls hit the guard AC exactly, 2 of them will hit (and, since gnoll attacks deal 5 damage, deal 10 damage to the guards, absorbed by their units with no overkill and,  should they drop any units, trigger the entire formation’s gnollish second attacks). If they beat the AC by 2, 3 will hit (15 damage). By +4, all 4 hit (20 damage). If they miss the AC by onky 2, 1 of them still hits (5 damage). Remember, this is 1d20 roll.
Then, the archers. Remember, they’re in the back rank, so all the ACs are adjusted. On an exact hit, 1 hits (round down; 5 damage. If you wanted to, you could split the difference and call it 7 damage. Just be consistent). +2 get you 2 hits (10 damage), +4 all 3 (15).
Then the gnolls attack the heroes. No need for subdivision, they use 7 attacks against each. If they exactly beat the PC AC, they deal 7/2=4 hits (20 damage). If they hit/miss by +2, they get an additional 7/4=2 (rounded reasonably!) hits either way. If it’s a hit/miss by +4, they get an additional 7/8=1 hits, maxing out 7 hits on a success, or leaving one hit on a miss; a miss by 6 resolves that.
Then the gnoll captain gets an attack in; one mass attack on each unit in the formation and one targeted attack on one hero. His hits or misses are atomic, with no multiplier.

On the players turn, they can return the favor. Their guards make a roll (representing 4 attacks with the same +/-2 representing halves that hit) the archers (3 attacks), and finally the cleric (who will swing at the captain and the gnolls) and the wizard (who casts fireball to similar effect).

Whew!

All-in-all, the mini-wargame thing was awesome, and I will definitely be using it again.

“How long do you want to spend?”

The hot tech in RPG skill systems these days seems to be a cluster of concepts related to “failing forward”, ensuring that the outcome of a failed skill check is interesting so that play can continue in one form or another despite flubbing a roll.
This goes along with other concepts like only asking for a roll if both outcomes are interesting, giving mixed outcomes on skill checks so that a failure is just success at a cost (and the player has some authorial control over what their failure looks like), explicit stake setting, and so forth.
But let’s focus on that failing forward thing for now. In D&D, some skill checks have always been fail-forward: if you fail at moving silently, you get detected, and play that out. If there’s nothing to detect you, then the failure didn’t do anything but ratchet up tension, and that was in the service of the story too: that seems fine. Failure doesn’t stop the story, it changes it. Into a story about the inside of some guardian Beastie’s gullet.
Some skill checks are not (exactly) fail forward, though: if you don’t pick the lock or climb the wall or bust down the door or whatever, you’re still in status quo ante and the die roll didn’t mean anything but a wasted 6 seconds. Out of combat, even the threat of a fall doesn’t mean much, since while it threatens a fall from great height, playing out each of the segmented climbing steps is a giant pain in the butt and most DMs I’ve seen let a single check carry for the whole height.
Yes, you can be in a situation where you need to get through the door right now, but if you aren’t, what are we to do?

3/4e kind of solved this with take 10/20 rules, statistical arguments about capabilities over time: if you can make the check 20 times, assume you roll a 20 on the die and go with that.

I reject this concept in place of the simple “how long do you want to spend?” system. It has die rolls that natter without degenerating to the DM deciding on a binary “you can/not do this depending on whether the DC is 20+your modifier or not”.

Here’s how it works.
In round-by-round combat, you can only spend 6 seconds and accomplish things you can, y’know, do in six seconds. These rules don’t really apply. If you fail on a thing, you can try again next round, and the round thereafter, and so on.

Out of combat, the player says what they’re doing (“I’m searching the room!”, “I’m picking the lock!”, ” I’m rigging up climbing gear and climbing the wall!” and so forth). The DM sets an expected period and a difficulty class for the task. The DM should inform the player of the period, and also hint at the difficulty (though that may be influenced by hidden factors).

Expected period: example tasks.
1 round: busting down a door, manipulating a device, listening at a door, climbing 30 feet
1 minute: searching a 10×10 section of corridor, picking a lock, climbing 300 feet
10 minutes: searching a 30×30 room, skimming a book for clues, building a barricade, climbing 3000 feet
An hour and a half: searching a 100×100 room, reading through a book thoroughly, hunting for game, climbing 30,000 feet (seriously?!)

Ask how long the players are willing to spend on this pursuit.

Adjust the narration of how long the task actually took by the amount by which the player’s check beat the difficulty class (or failed to do so!). If the players are unwilling to spend the amount if time this would indicate in order to succeed, they spend as much time as they were willing to spend, get whatever proportionally success seems reasonable, but fail overall. They may adjust their answer upwards now if they want to just keep trying.

Success can be faster!
If the roll beats the DC, the time the task took was pretty much the expected period.
If it beats the DC by 5+, the task is accomplished in 2/3 of the expected period (6* the next shortest period).
By 10+, 1/3 of the expected period (3* the next shortest period).
By 20+, 1/10 of the expected period (simply use the next shortest period).
Consider a bonus action 1/3 of an action, and “not an action” 1/10th of one.

On the other hand, failure can be slower.
If the roll misses the DC, the player may spend longer to increase their chances of success.
They may spend half the next largest period for +2 on their roll, the entire value of the next largest period for +5, or (at the DMs option) two periods up for +10.
However, if what they are attempting has hazards for failure (such as climbing under hazardous circumstances), those are applied before the character has the potential to spend longer to succeed: they fail.

Example of play:
Cwinn the dwarf, armed with a crowbar, wants to break through a stout wooden door in the Dungeon of Hathory. Cwinn’s player, Chris, declares his intention to break down the door and that he’s not leaving ’till it’s broken. The DM sets the DC at 10, and Chris rolls for it — with advantage from the crowbar. The total check value is 17, handily more than 10.  Since this isn’t more than 10 points higher, but is more than 5 points higher, the DM determines that it takes 2/3 of the next shortest period. Since that base period was 1 round, it’s not enough to matter here: Cwinn busts open the door.
However, if we consider Lellin, Cwinn’s wizardly companion, separated from the rest of the group. Louis, Lellin’s player, makes a similar attempt. With Lellin’s total of 4 (tired, hungry, lacking crowbar and not up to the task at the best of times!), Lellin can only bust down the door at the cost of 10 minutes effort. Since that’s two orders of magnitude more expensive, the DM may also rule that Lellin is unable to bypass the door until the situation changes.

Why would you do these things?
Because the amount of time characters spend on a task reveals how much the player wants to risk failure and time is always secretly a resource.
If the players characters have to climb a cliff, it’s not particularly difficult, but the DM still wants to roll for random encounters or whatever, the interesting roll isn’t the climb check: it’s the random encounter roll. These rules give the DM a quick way to approximate how long a task will take and then move on to whatever’s interesting, without saying “you fail on your sixth attempt, but may retry for a seventh in 6 seconds!”
That kind of narration works well when the environment is chaotic, changing from round to round, but most skill check scenarios are static, so the only interesting “partial success” outcomes relate to resources expended.
TL;DR: it strikes the balance between the DM making a snap judgment without any guidance and boring the whole table with a thermodynamics simulator.