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In Need of a Simple Dice-Combat System

14 replies [Last post]
Joined: 03/15/2012

Some of you guys may have seen/heard that I'm working on a card-based RPG game. Right now, I'm having difficulties settling on (or just coming up with) a combat system that works with my goal. The idea is that this game is based on the familiar RPG platforms, which frequently use D20s, but is simplified to be playable from level 1 to level 10 in under two hours. To that end, combat should take about 10-15 minutes per encounter, preferably even less. I want to keep the game approachable, as I think that anyone who wants to play a game with lots of record-keeping and mathematics is going to just play D&D, Pathfinder, or some similar p&p RPG.

The current method:

Current method uses a D6. All numbers 1-5 are doubled (2,4...10) with 6 being a Critical. Whether the Critical is a success for failure depends on whether or not the character is using a weapon that they are proficient with. Monsters are always assumed to be proficient with their weapon.
This system is based on a direct transition from the D20's % system. You roll to beat the targets 'Defense' value in order to hit them, and then roll damage according to your attack, which weapon you have equipped, and any modifiers (strength, class ability, magic items, etc).

The Problem: How do I differentiate Weapons under this role, and when everything is hinged on just 6 random outcomes (technically 7 if you count the possibility for critical failure) plus modifiers? Also, do 'Critical Hits' automatically hit, or should they have a better effect? If they auto-hit it could be a bit redundant, since a natural 10+mods will probably also hit. And damage? What should I do for critical damage? Let it count as 12 if you are proficient or a 0 if you are not? Or should it double? Also, only having a D6 at my disposal means that weapons are limited to only having modifiers or additional dice to differentiate their damage profiles.

The Proposed Method:

Someone pointed out the game Super Dungeon Explorer, and my personal love affair with Death Angel, both of which use dice with symbols. For Death Angel they have numbers on all faces from 0-5, and Skulls on half of those. When rolling to hit, you are trying to roll a skull. For SDE, you have Red dice and Blue dice, which have "hit" symbols on them. The Red die is considered "stronger" as it has more 'hit' symbols on it (4 rather than 2, if i recall).

The Problem: this works well, but it changes the 'Defense' mechanic. As Def can be modified by armor and natural abilities, how would I set it up so that you bounce hits? And, further, how do I manage damage under this system?

I have considered issuing players with multiple dice - one for hits, and then an additional 4 dice for damage, split into 2 "greater" and "lesser", numbered accordingly:
Lesser - 1,2,2,3,4,5
Greater - 3,4,5,6,7,8
All weapons would then be combinations of those 4 dice, denoted as a number and letter perhaps. Something like a dagger might only do 1L damage, while a greataxe might be 2G, and the magical hammer Mjolnir might be 2G1L.


MarkKreitler's picture
Joined: 11/12/2008
Card-based RPG = COOL!

Hey Sly,

First off -- GREAT idea, over all!

I've been tinkering with a card-base RPG system for a bit, too, and I'd love to see how you've tackled certain problems -- but that's for another post.

For *this* reply, let me make sure I understand what you're asking:

1) You're looking for ideas on how to differentiate weapons when using a single 6-sided "to hit" die.

2) You're looking for commentary about systems like SDE and Death Angel, which use non-standard sides on the "normal" 6-sided die.

3) You're looking for commentary about the proposed damage system, with greater and lesser dice.

Before diving into those three subjects, I have to ask: what are your design goals for this system?


Based on your description of the game, I would say speed and simplicity are your two highest priorities, but that's a guess. If I'm wrong, everything I say will be crap. Even if I'm right, it might be crap, so feel free to disregard. :)

I'm going to start a new post for the individual answers so this doesn't turn into a wall of text.

larienna's picture
Joined: 07/28/2008
I did not read the entire

I did not read the entire thread, but people who comes from the D&D world somewhat have imprinted in their mind that to resolve battle you need to make attack and damage rolls. I know that because I have been there.

But there are many different ways to simplify things to make sure it run faster by reducing the number of dice rolls. The general idea is to combine stats and rolls together. The disadvantage is that you have less variety to create equipment and effects, but since you want your game to be simpler, that should not be a problem.

Here is a few quick example:

In final fantasy tactics, armor gives HP. So in that case, there is no armor rating to consider.

You could have various success level to combine damage and attack roll. If you roll higher than value A, you score full damage. If higher than B, you score half damage, else you miss.

I don't remember well, but D&D miniature recorder HP/damage in slice of 5 points if I remember correctly.

In death angel, they go even easier: if you roll less than the number of monsters, you die.

That's another things, you could not keep track of damage points. Maybe the first time a monster/character is hit, you flip it in wounded status, and the next time it's hit it dies. If you roll very high, you can kill it instantly of course.

So there are various simplification possible by combining of simplifying stats. Be creative.

MarkKreitler's picture
Joined: 11/12/2008
Question 1: how do I model weapons in a single-die system?

1) How does one differentiate weapons in a combat system that uses a single 6-sided die?

Your biggest asset are the cards in your RPG. Some of your big challenges are: only 6 results per die, a flat probability distribution (if you're only using 1 die to compute results).

Some ideas that come to mind:

1) Encode a "to-hit" chart on each weapon's card, with different different cards having different charts

2) Allow combatants to play their weapon cards either offensively or defensively each turn, adjusting combat results appropriately.

3) Combine 1 & 2, putting a "defensive" and "offensive" table on each weapon card, which can then be played right-side-up or upside-down to determine which chart is used each turn.

4) Consider changing the role of defense. Back when I played D&D, it used a cross-reference between attacker level and player armor class to determine the chance of success. If you adopt that system, you'll probably have to use tables. Alternatively, you could use a system like HERO, which turns armor into a straight subtraction from the damage role. This removes it from the "to-hit" role, simplifying things.

5) Consider using more dice. D&D uses a single "to-hit" die, but by using tables it generates a wide variety of mathematical success curves. If you use more dice, the probabilities already follow a nice bell curve, and you can get rid of the tables while still having an interesting feel to the game.

For example, you could use a symbol system like SDE or Memoir '44. The faces on the die could be skulls, drops of blood, shields, blanks, whatever. Then, you could put different symbol combinations on each weapon card, signifying different results. For example, 2 drops of blood on the dagger card might be "1 pt of damage," whereas the same result on the long sword might be "3 points of damage," because it's a more "powerful" weapon (and probably costs more).

Results need not be shared by all weapons. For example, the dagger might have a "skull + blood + shield" result that signifies a "back-stab" that does 2 points of damage and ignores armor, while the long sword doesn't have that combination at all.

I use a variation of this in my card-based RPG combat system. I use color dice, where "white" is a "wild" result you can flip to any color, red = damage, blue = defense, green = movement, yellow = special, and black "kills" the die, removing it from re-rolls. On a player's turn, he divides up his dice into attack and defense piles. He rolls his attack dice and subtracts off any black results. Blue results he sets aside for his defense plays. All others he uses to build color combinations that match "abilities" on his cards. For example (it's a superhero game), a character with Energy Blast would have the following card:

Energy Blast
1+ red: damage = red pips
1+ green + 1 yellow = "force blast" = pushes enemy back spaces equal to green pips

There are 4-6 results per card.

As the player is attacked, he rolls his defensive dice and totals blue pips, using those to activate various defensive abilities on his cards. He might even have defensive abilities on his Energy Blast cards, like:

1+ blue & 1 yellow = "timed blast" = subtract blue pips from incoming damage

Black dice are always removed until the start of the next turn, so the more you roll, the greater the chance that your dice pool will become smaller.

It's a simple model that's easy to understand and has worked well, so far. Calculations are all single digit, color-counting operations anyone can do.

Joined: 03/15/2012
Speed and Simplicity are

Speed and Simplicity are definitely my priorities, at least for combat. The idea behind the game is based on experiences with my friends who hate the 'RP' aspect of RPG. They just want to build bad*** characters, get into combat, and smash face. And honestly, that's what most RPGs are boiling down to these days (who *really* cares about RPing in WoW?).

So yes, while there are lots of options for skills and equipment (think D&D 4e) and character classes, the idea is that combat should be quick, brutal, and above all - entertaining. Going through several encounters (10-12, max 15) in a single sitting win or lose is what I'm aiming for.

Note - it's a party vs. the deck game, if that modifies your answer at all.

MarkKreitler's picture
Joined: 11/12/2008
That helps!

Thanks for the extra info, Sly -- that definitely helps.

Players vs deck with an emphasis on speed and simplicity means you could abstract out a bunch. Do you need both "to hit" and "damage" in such a system? If not, you've eliminated 50% of the rolls right there.

If building bas*** characters and smashing face are the goals, you don't have to worry about accuracy of the simulation, either. This frees you up to make some epic powers.

As an example, go back to the "color dice" example, above. Suppose that each player drafts a hand of cards to represent his character. Each card has a few abilities with various "mana" requirements. The colors on the dice represent different flavors of mana. Each turn, players divide their dice into "offense" and "defense," then roll their offense dice to try to activate powers from their hand. Think of it as "Magic: The Gathering" with each player holding a portion of the deck and land cards replaced with color dice roles. Goodness knows some Magic cards can do obscenely powerful things if the mana cost is high enough. You could do the same thing. If weapons are represented by cards, you could make each weapon feel unique by varying the mana costs and available abilities.

TLDR: D20 systems are great for what they're trying to model, but you have different requirements. Don't hesitate to abandon the model in favor of different mechanics whose math favors your design goals. I think your instinct to examine SDE is a good one.

Have you started a journal for this game?

Joined: 03/15/2012
Wow, missed the replies, and

Wow, missed the replies, and they were AWESOME. Thanks guys.

I do realize that I'm very engendered in the "hit > wound > result" method, as both a D&D player, but also as an avid Warhammer gamer (which sucks, because everyone hates their CC method). Breaking that down for me and just reminding me that there are alternatives was great. You'll also see some of the suggestions you guys gave implemented in my ideas below.

Here's the method I'm putting together from your replies:

Components - Red dice, Blue dice (major and minor attacks/defense) with 'Hit' and 'Shield' icons. Red die has 4 hit, 2 shield. Blue die has 4 shield, 2 hit.

Monster to Character Attacks
Each monster's "attack" is a number of red/blue dice. During the monster's turn, add all the monsters' attacks together and roll them. A 'Hit' will cause 1pt of damage to the character. The character then adds up their Defense (from their character, plus any gear or abilities) and rolls them. A 'shield' will negate 1 hit.

Character to Monster Attacks
Each Class has a basic attack value, and weapons provide additional dice. Powers will also modify this (2W would mean roll double the number of dice shown on your weapon). Roll the dice and tally the number of hits. Each monster then has a certain number of hits required to kill it.

-This makes player interaction important, because monsters become more dangerous as they "mob up"
-This is definitely quick, fast, and visual, requiring no numbers or charts

-Lots of dice could increase production cost by a good bit, as well as be intimidating. How many would you consider to be a good number?
-This is practically identical to the system used by 'Super Dungeon Explorer'

**there is a journal, but it's more of a read-through of the rulebook as the game develops. It's called 'Forgotten Gods', but that's just a working title for now.

MarkKreitler's picture
Joined: 11/12/2008
Solid system

That's a solid system. Like you say, it's fast and visual.

One danger is its lack of scalability. Your earlier post implies you want players to level significantly over the course of a session. How much do you see their damage numbers changing over the course of those levels? Said another way, if at level 1 I'm battling kobolds that do 1-3 hp per attack, what am I battling at level 15? How much damage do lvl 15 creatures do? 5-10 hp/attack? 20-30 hp/attack? In order to feel like I'm progressing significantly, the damage has to increase dramatically, and that means the number of dice increases equally dramatically.

Decoupling the symbols from literal numbers can fix this (there are other ways, too). For example, instead of 3 hit symbols equaling 3 points of damage, 3 hit icons references a particular power on the monster's card, which states how much damage. For example, a 3-hit-symbol attack by a lvl 1 kobold does 3 points of damage. The same 3-hit-symbol attack by a lvl 15 dragon does 50 points.

You might also want to consider trading in one of those blue hit symbols for a "special" symbol, like the star in Memoir '44. When players roll stars, they have the option to activate special abilities. For example, Drow Elves might be able to life leech hit points from their enemies when they roll stars. Another example: players with the "spear" weapon might be able to damage flying targets when they roll a star.

The "special" symbol lets you add variety without adding complexity.

All that said, the base system you're suggesting is solid, and will serve as a great foundation from which to tackle any curveballs you find during playtesting.

Joined: 03/22/2012
Critical = reroll

A system I remember hearing about used the rule that every crit lets you roll again - so if you were working with a normal d6, then you've got a 1/6 chance foreach value 1-5, then 1/36 for 7-11, 1/216 for 13-17, and so forth. It means that you'll never do damage that's a multiple of 6, but that's not necessarily a deal-breaker. I could even imagine some weapons having a "weak" critical roll where a 6 lets you roll just once more for bonus damage, while other weapons have a "strong" critical where you keep rolling.

This could also be extended to dedicated dice like the system you're discussing here - the "critical" symbol deals a fixed amount of damage plus an additional roll - or like Mark says just above, you could have special abilities on a roll of "star", some of which might be things like "roll the damage die 2 (or 3 or whatever) times and do that many damage" with some kind of explanation of what rolling another star does.

larienna's picture
Joined: 07/28/2008
Take a look at arkham

Take a look at arkham horror's combat system (rules are online). It's a pretty small system that has a lot of variables into the roll that allows to resolve encounters pretty fast.

Joined: 03/15/2012
I'm having a very hard time

I'm having a very hard time tracking down a .pdf that I can actually open to read for Arkham, and there are at least 2 versions of the game (the Chaosium and FantasyFlight versions, plus expansions). What I've gathered almost brings me back to the original idea though. Monsters have a Def rating displayed as "+/- X" added to character's dice rolls, and a HP displaying how many hits it will take to kill them. There are two modifiable attack characteristics - essentially "how many dice" and "successful results per die".

Monster Scaling in the Red/Blue system proposed above would be similar to:
L1 : 1B
L2 : 1R
L3 : 2B
L4 : BR
L9 : RRR

That would require 3 dice of each color, plus dice for the defenders to roll. Adding in monsters to the attack makes things even more difficult - 2 L9 monsters attacking together for example would require rolling 6 red dice.

So it looks like my options are: lots of dice with simple visualization, or lots of math with fewer dice. Decisions decisions.

Morgothrond's picture
Joined: 04/03/2012
What I've done:

1 - Roll only damage. Reduce by armour armour value. Each weapon is a different dice.

2.- Have mosnters that are not "bosses" be minions (1hp) with tough tactics.

3.- Roll vs defense, then apply standard damage per weapon. ANd have baddies with low HP but good tough tactics.

Normally this works for me if i wanna speed up combat.

MarkKreitler's picture
Joined: 11/12/2008
Maybe, maybe not

> So it looks like my options are: lots of dice with simple visualization, or lots of math with fewer dice. Decisions decisions.

This depends on your rules for scaling multiple attackers. It also depends on how players' abilities scale as they gain levels.

Take Memoir '44 for example. A single unit consists of 4 members. As long as a unit contains any member, it rolls its full attack. Once all members are destroyed, the unit is gone. In other words, unit strength is equivalent to hit points. This might seem counterintuitive, but the higher the strength, the longer the unit lasts and the more damage it does.

This exact system probably isn't a fit for your game, but it shows an alternate way of thinking about the problem.

You can also scale things non-linearly. For example, adding an identical monster promotes a blue die to a red. If there are no more blue dice to promote, add a red die. If you compromise on the math a bit and use a table, you can expand the promotion system a bit. All monsters have an "attack strength" which you add together to get a final result, which you then look up in a table to get the final number of attack dice.

I recall that the designer of Memoir '44 also released a fantasy-themed game with a similar dicing mechanic. I don't remember the name, but it should be easy enough to track down on BGG. You might take a look to see a different way of thinking of things.

EDIT: the game is Battle Lore:

Joined: 03/15/2012
< Monsters that aren't

< Monsters that aren't "bosses" are minions (1hp) with tough tactics
As far as the AI in my game, it's pretty limited. Each of the classes is color-coded based on it's archtype. There are 4 archtypes in the game - Guardian, Skirmisher, Leader, and Arcanist. Classes all fall into one of those archtypes. Each monster has a 'Target Priority' track on the card, which lists off the 4 colors from left to right. When you draw a monster from the deck, it is automatically assigned to the character who's archtype color appears first on the priority (there are rules for multiple copies of 1 arch in a party, don't worry).
Characters can have up to 2x their current level of baddies piled up against them before they are "maxed out". At this point, any monster that would target that character first, will instead target the next available character on it's priority track.
Some monsters have attacks that change based on which archtype they are fighting (most notably the bosses), and some monsters are designated "ranged" and can therefore attack without actually being counted in combat against a character (until a character uses a "draw" ability to pull them into combat). But that's about it for 'tactics', so I don't know what you mean making them harder tactically.

< Memoir's "Squad" system | stacking attacks
I have thought about having monsters of the same type or level "stack up" in some way or another so that they become more of a threat as characters get overwhelmed. Since the dice are now looking like they'll have numbers on them instead of just generic symbols, I was thinking of having all the monsters combine into a single massive unit. Under your idea, I could go for a simple 2:1 swap between Red and Blue dice. There are 3 of each color in the box, if you have a swarm that calls for a 4B attack, you would instead translate it to a 2B+1R attack. If you kill one of the monsters, they go back down to a 3B attack. They also each get +1 to their Hit modifier for each other monster in the stack. That's the real kicker - the more beasties you have against you, the harder it becomes to block their attacks.

Again, this works well until you hit the Red-level attacks. What happens if you are in a higher level encounter and you have an attack calling for 4R? Does it become 3R + 2B?

I think what I'm going to end up doing, is setting up the game so that the quality/quantity of the dice doesn't change as often, and instead, the modifiers and hitpoints advance. This will hopefully keep the number of multi-red situations to a minimum, and restrict them to the higher levels. I'm also implementing a rule that states that if you kill a monster that is equal to your current level or below, you remove it from the monster deck. Otherwise I'm going to end up with stacks of 20 L1 creatures fighting against a L10 Warrior.

larienna's picture
Joined: 07/28/2008
Here is Arkham Horror rules

Here is Arkham Horror rules directly from the publisher

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