A friend of mine wanted me to post this minimalist RPG system I wrote back in 2007. So, here it is. I suggest using it as a starting point in making something that works best for your group. Yes, this is the entire rulebook.
The GM is always right.
Characters
Each character has a number of traits, abilities, and skills.
Traits represent the raw talent or power your character possesses in a field.
Example traits might include cunning, intelligence, fortitude, or agility.
Normally, traits can be -2 through +4.
Abilities represent general skill-sets which the character has learned.
Example abilities might include martial arts, stealth, acrobatics, or magical lore.
Normally, abilities can be +1 through +4.
Skills are more specific than abilities, and represent specific prowesses.
Example skills might include tracking, lock-picking, feinting, or swimming.
Normally, skills can be +1 through +5.
Challenges
Before playing, pick a kind of dice to use (I prefer d6) and stick with that for the rest of the game.
All challenges are made by rolling dice and counting the number of results that equal or exceed a Target Number.
Target Numbers are based on the inherent difficulty of an action. Jumping across a small gap would be easy, while jumping across a large gap would be hard. Don’t even bother rolling trivial challenges.
| Difficulty | d6 | d10 | d20 |
|---|---|---|---|
| Easy | 3 | 4 | 7 |
| Normal | 4 | 6 | 11 |
| Difficult | 5 | 8 | 15 |
| Extreme | 6 | 10 | 19 |
For any solo challenge, the GM will require a certain number of successes for the character to succeed in their action. In many instances (such as music or athletics), more successes indicate a more impressive performance.
When characters oppose one another, treat it as though both characters were performing solo challenges where the victor is the one with the most successes. In this circumstance, the degree of success is equal to the difference, rather than the absolute number of successes.
* * *
A player rolls a number of dice for a challenge depending on their character’s attributes and the circumstances of the challenge.
Each challenge uses a trait, chosen by the GM. The player then chooses one ability and one skill. If the GM decides that either are unfit for the test at hand, the player cannot use them (and may not change their choice). The player then rolls a number of dice equal to:
1 + trait + ability (if any) + skill (if any) + circumstance modifiers (if any)
Unless a challenge is impossible, all characters get one base die, which cannot be removed due to modifiers.
Circumstantial modifiers can include assistance from others, low visibility, weariness, wounds, magic, distraction, etc.
Character Creation and Advancement
Before the game can begin, the GM must provide a list of traits. These traits should optimally cover all character archetypes that players want to use.
All traits start out at +0. Each player has two points which can be spent increase a trait (+0 -> +1 or +1 -> +2). Traits may be reduced to -1 to gain an additional point. Normally, a trait cannot be increased above +2 or reduced below a -1.
If a player wants to play a specialist, however, they may opt to reduce a +0 to a -2 in order to increase a +2 trait to a +3. This specialization may only be done once.
Starting characters then gain 20 “triumphs” which they can use to buy up skills and abilities, described below. 20 triumphs is intended to represent a starting hero, and the GM is encouraged to allot more for creating “experienced” heroes.
“Triumphs” are the units used to keep track of character advancement. Whenever a player does something difficult and important, the GM is suggested to give them a triumph. When a character is in a situation where they have the opportunity to increase a trait, ability or skill, (such as when creating a character) they may burn triumphs to do so. The number of triumphs it takes to move from one number to another depends on what is being increased.
| -2 -> -1 = 1 |
| -1 -> +0 = 2 |
| +0 -> +1 = 3 |
| +1 -> +2 = 4 |
| +2 -> +3 = 5 |
| +3 -> +4 = 7 |
| +0 -> +1 = 2 (Gaining a new ability) |
| +1 -> +2 = 3 |
| +2 -> +3 = 4 |
| +3 -> +4 = 6 |
| +0 -> +1 = 1 (Gaining a new skill) |
| +1 -> +2 = 2 |
| +2 -> +3 = 2 |
| +3 -> +4 = 4 |
| +4 -> +5 = 6 |
If the task of learning is difficult (such as without a teacher) the GM may require a challenge to improve.
Characters start with whatever items or equipment are considered appropriate for the setting and the character. If in doubt, ask the GM.
Combat
In addition to traits, abilities, skills and gear, characters have a number of health boxes which are an abstract representation of their physical condition. The number of health boxes a character has will depend on the style of game that the GM is running and the physical toughness of the character. GMs are encouraged to tie a trait, like “Health” or “Fortitude” to the number of Health Boxes a character receives (minimum 1). I suggest using a base of 10 boxes. Gritty games may go for 5 or even 3. When a character takes damage, mark off a number of health boxes. When the last one is marked, the character typically goes into a coma or dies, depending on the circumstances. A character’s health should always be taken into account when determining the “circumstances” of a challenge.
Combat can also vary, depending on GM. Presented below are three ways that I suggest handling combat.
Fearsome Challenges
Perhaps the simplest way to deal with combat is simply to make it a series of deadly challenges.
Imagine a group of explorers venturing through a forgotten tomb. They come upon a spike-laden pit trap. Jumping across the pit might take two successes against a difficult target number, with failure dealing 4 health boxes of damage, and the extra problem of getting out. Now imagine the explorers come across an ancient tomb guardian. The guardian is slow, and all the players can take actions before the guardian acts. When it does, it swings it’s hammer at a single character, forcing a challenge to either block or move with failure meaning the victim takes 4 health boxes of damage. Under this system of combat, there is no difference between an environmental hazard and an intelligent opponent, except that opponents are generally deadlier and more adaptable.
This system allows the GM to avoid rolling dice, which lets them stay focused on the group. To determine the number of successes to dodge the attack of a humanoid opponent, just assume that they roll all average. That is, if they are looking for a “normal” target number, just make their degree of success = half their dice pool.
Using this system, determine if enemies act first, then take turns where the whole party acts in whatever order they want (though only within reason).
Single-Action Roundtable
Good for dueling, this system breaks combat down into a number of rounds, where each player takes a single action.
Each character, at the beginning of combat, performs a challenge to act first, comparing degrees of success. In the case of a tie, the character with the highest “agility” trait (or equivalent) acts first, or the GM simply decides. Each character then acts in turn, taking a single action. Typical actions involve directly attacking the opponent, or modifying circumstances to get more dice on a future attack.
Attacks are handled as contested challenges with the defender. Stunned or surprised characters cannot defend. If the attacker wins, he or she deals damage equal to their degree of success (plus any modifier from weapon or armor). If the defender wins, they gain a counter-attack advantage on their next turn of a single die.
Bloodbath
This system is good for games that favor violent, or unpredictable combat. In Bloodbath, all characters decide on their actions in secret and act simultaneously. The results of a round of combat depend on the nature of the actions involved.
Independent Non-Challenge: An example of this is two characters that run away from each other. No rolls are made, and both characters successfully withdraw.
Independent Challenge: An example of this is two characters that attack each other. Each character rolls a solo challenge to hit and deals their raw successes as damage to their opponent (plus any modifier from weapon or armor). This can mean that both characters kill each other, if they roll high enough.
Conflicting Challenge: An example of this is a character that attacks a defending or fleeing character. The action is made as an opposed challenge, where the victor is the only one to have their action take effect, and their degree of success is the difference between the rolls.
Asynchronous: An example of this is a character that attacks a character trying to focus on something. In instances where one action (like attacking) is unaffected by another action (like focusing), but not vice-versa, the action that is not effected works and the other is disrupted.
Bloodbath can become unwieldy in non-one-on-one situations, and favors power in numbers.

One Comment
Some advice:
On Monsters and Races:
Remember that the GM is always right! Mastery is built to be flexible, not all-encompassing. If you, as a GM, feel that dwarves deserve stat mods – do it! It is because of this that the system doesn’t handle monsters or races. These things differ so much from one world to the next, that it’s on the shoulders of GMs and supplement writers to come up with rules for such things.
Skills and Abilities:
As a GM, the biggest task will be learning to classify skills and abilities and to call “not applicable” skills when players try to use them. This can be hard, as a player can fail simply because you don’t think farming ability helps classify wild plants. Combat can be especially bad, as powergamers will instantly create “Skill with Erchax the Longsword” and try to pass it off as a skill. Skills are more powerful than abilities, and should be much more specific, and very rarely cover simple attacking. Parrying, for example, makes a good skill. Counterattacking with a specific weapon is a good skill. Both of these are only usable in certain situations, which is why they’re skills and not abilities. Abilities represent professions, general skillsets and skill with weapons. When considering whether something is a skill or ability, also take into consideration the world and type of game you’re playing. Engineering might be an ability in a steampunk setting, but in a dark ages world it would probably only be a skill.
Don’t be afraid to say that certain actions are only possible by characters with points in a specific skill. I can’t do magic, so why should a farmer or a barbarian? This even applies to abilities, though less so. I may not be able to do a cartwheel unless I have acrobatics, for instance.
Lastly, say no to skills and abilities that don’t match up with a test! Don’t let your players re-pick different skills or abilities once you turn the first ones down! (unless you really think they deserve it) If players know that a bad choice will result in no extra dice, they’ll be more likely to pick the most realistic skills and abilities. Disallowing skills and abilities also forces players to get creative and tackle problems from different angles.
Weapons and Armor:
Weapons in mastery are a bit vague, much like the setting itself. The power level of weapons and armor depends on the technology of the setting and also how gritty the GM wants to run things. High weapon damage means more deadly combat, while high armor values tend to make for a more “epic” game (as high armor tends to mean a generally higher expected damage).
Remember that weapons are more than just that single number. Some weapons (such as daggers) are easier to wield in tight quarters and conceal. Others (such as flails) might be difficult to wield. Some will require special conditions to be effective (lances) or require more time to use (ranged weapons). If you feel that an attack deserves a damage modifier (such as a killing blow or a point-blank shot), propose it to the GM. And as always, modify these numbers as you see fit to make the game that is fun for you.
Proficiency is also important with both weapons and armor. In cases where a character attempts to use a weapon without any skill or ability, the GM may decide to impose any number of circumstance penalties. Armor, unlike weaponry, has no associated skill or ability (under the defaults), but the GM has full right to impose penalties on any number of things, especially if the wearer of the armor is unfamiliar with it.