Jazz 3.0:JazzCore

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JazzCore is the base rule set for Jazz. For games set in the "real" world, JazzCore is sufficient. For more outlandish games, additional rules may be necessary (or you can just wing it).


What you are reading now is JazzCore (or just "Jazz"), the basic structure of Jazz. The "genre modules" for Jazz (i.e. JazzApocalypse, JazzSorcery, JazzVoodoo, etc.) are still very much under construction. In the fullness of time you'll be able to use Jazz for post-apocalypse games, sword-and-sorcery games, and so on, but at the moment the game mechanics only support less outlandish genres. There is still a lot of room for heroic characters: extraordinary strength and balance, a preternatural sense for danger, etc., are easily done. But for the time being, more blatant violations of what we tend to call reality would have to be handled case-by-case by the GM and players.

Character checklist

  • Concept: a few words summing up who or what you are
  • Motivation: why you do what you do
  • Descriptors: one primary, and one or more secondary
  • Flaws: one flaw
  • Health points: 5 x (survival descriptor rank)
  • Fringe points: 3 x (fringe descriptor rank)
  • Fate dice: one die


The "rank" of a descriptor is the number of dice in the descriptor. The total number of ranks to be allocated among the character's descriptors and the maximum rank of a single descriptor are dependent on the "fiction level" of the game being run. A higher fiction level means more and higher ranks.

Fiction level

The less realistic the game, the more ranks the character may distribute among her descriptors, and the higher the ranks of those descriptors may be.

Table: Fiction level
Fiction level Total ranks Max rank
1 Mundane 2 1
2 Exceptional 4 2
3 Elite 7 3
4 Heroic 11 4
5 Legendary 14 5
6 Mythic 18 6

The most important thing about descriptors is not that they are effective in combat or useful in any possible situation. You could make up a "tough-as-nails soldier" who is both "brilliant" and "strong-willed", but a group of such characters is going to be as dull as dishwater. Combat is a small part of a role-playing game. Make your character someone interesting to have around. You will have more fun, and the people playing with you will have more fun.

Also, keep in mind that not all descriptors actually mean the same thing. One soldier may know how to drive tanks and rebuild engines, but know nothing about logistics. Another soldier may be able to set and disable explosives, but know nothing about artillery. You (with the GM's help and consent) decide who your character is and what they can do -- and what they can't do. Just because your character is a British secret service agent does not mean that she knows everything about everything.

You can see from the total ranks and max ranks permitted at each fiction level that unless a character has fringe descriptors, she will have at least two or three descriptors. This should allow enough descriptors for anyone to describe a well-rounded, interesting character.

Primary descriptors

The first descriptor a character has is her "primary descriptor". The character's primary descriptor is a broad description of her basic character type. It is helpful to use an "adjective + noun" structure for the primary descriptor (e.g., "upper class necromancer", "brawny scientist", "steely-eyed killer"). A character's primary descriptor is deliberately broad, and is intended to cover a wide range of skills and abilities. Each "genre" will offer a list of "typical descriptors". The player may choose a descriptor from this list, or make up her own (with GM approval).

Secondary descriptors

Descriptors after the first are "secondary descriptors". Secondary descriptors are relatively specific (e.g., "drunkard", "scientist", "gunslinger"). If a specific task could apply to more than one descriptor, the player may roll whichever descriptor has the most dice. Each "genre" will offer a list of "typical descriptors". The player may choose secondary descriptors from this list, or make up her own (with GM approval).

Fringe descriptors

Some descriptors grant a character powers beyond the realm of what most other characters can do, no matter how high their descriptors are. These abilities might be the result of magic, mutation, specialized training, or some other source. These "fringe descriptors" are noted with a "F" after the rank of the descriptor (e.g., "3F").

Fringe descriptors may be either primary or secondary descriptors, and they cost twice as much as regular descriptors. For example, when creating an elite fiction level character (max descriptor rank 3), a rank 3 fringe descriptor would cost six of the character's initial number of ranks to be allocated, while a rank 3 non-fringe descriptor would simply cost three ranks.

Any descriptor that permits the character to increase her weapon damage (e.g., "gun-fu master") or her armor protection value (e.g., "lucky bastard") is considered a fringe descriptor.

Universal descriptors

Universal descriptors are things generally known by everyone in a specific culture or time period. Universal descriptors could be commonplace abilities, like the ability to drive a car or use a telephone, or it could be a straightforward ability that everyone can attempt even without training, such as brawling or assembling a bicycle. Every character in a given setting is assumed to have rank 1 in all universal descriptors appropriate to that genre. These do not need to be written on the character sheet.

Missing descriptors

If a character is in a situation where she has no appropriate descriptors, she can normally use a universal descriptor (rank 1) to attempt the task. Only if the task is truly extraordinary, requiring specialized training or experience to even make an attempt (however feeble that attempt might be), would the character be unable to roll any dice at all.


A standard Jazz character has one flaw. Flaws should be something meaningful, preferably something related to the character's personality (e.g., "relentlessly curious", "driven to protect humans from nonhumans", "prone to reckless overconfidence"). If a fringe descriptor plays a major role in the character's background, the character's flaw can pertain to this descriptor (e.g., "must have hands free to cast spells", "must abide by complex set of taboos", "fringe points only replenish in a cemetery").

Player characters should have some reasonably common flaw, but NPCs can have esoteric, plot-dependent flaws. Each "genre module" will offer a list of "typical flaws". The player may choose a flaw from this list, or make up her own (with GM approval).

Health points

Health is a measure of how much physical abuse a character can take before she is out of the fight. The character's health point total is equal to five times the rank of her most survival-relevant descriptor (e.g., 5 x rank 4 = 20 health points).

"Survival-relevant" does not necessarily reflect combat training or sheer physical prowess (although of course it can). A "street-smart orphan" and a "wily scavenger" also have survival skills.

Fringe points

Fringe point are a measure of how often a character can use her fringe descriptors to perform extraordinary actions. The character's fringe point total is equal to three times the rank of her most survival-relevant descriptor (e.g., 3 x rank 2 = 6 fringe points).

Using a fringe descriptor does not always cost a point of fringe. The character only needs to spend a fringe point if she is using the fringe descriptor to perform an action which is truly extraordinary or supernatural. For example, opening an unlocked door or lighting a candle with a fringe descriptor would not cost a fringe point unless circumstances would have prevented the character from performing the task any other way.

The character may only spend one point of fringe per round, but spending a point of fringe permits the character to perform as many fringe-related actions during the round as the GM feels is appropriate.

Fate dice

A standard Jazz character has one fate die, which may be rolled any time the player needs to roll dice. The player can use each of her character's fate dice to improve one roll per game session. The player must decide whether to add one or more dice from her fate dice before any dice are rolled, and once one of her fate dice is used, it cannot be used again in that game session. The character may acquire more fate dice with experience.


Genre conventions

Each setting will have specific rules which apply only to that genre. These are called "genre conventions".

Rolling dice

When a character uses a descriptor, and the outcome is either contested or there is some random element involved, the player rolls a number of dice equal to the rank of the descriptor, and counts the dots. This roll is compared against a roll made by the GM (or a difficulty number the GM assigns). The attempt succeeds if the player's roll equals or exceeds the GM's roll (or the assigned difficulty).

Table: Task difficulty
Task Difficulty or Opposed roll
Mundane 4 1d6
Exceptional 7 2d6
Elite 11 3d6
Heroic 14 4d6
Legendary 18 5d6
Mythic 21 6d6+

Take the average

If the character is under no pressure, and there is no penalty for failure or there is no time limit, the player may "take the average", and assume that she would roll an average amount (rounded up in the player's favor): 4 for 1d6, 7 for 2d6, and so on. In effect, the character is treating the task as routine.

Note that combat -- whether it is physical (a gunfight), psychic (a battle of wills), or social (a marital dispute) -- typically involves both a time limit and a penalty for failure.

Take the max

If the character is under no pressure, and there is no penalty for failure and there is no time limit, the player may "take the max", and assume that she would roll the maximum amount (6 for 1d6, 12 for 2d6, etc.). In effect, the character is trying over and over until she does the best she is capable of doing.



Roll a combat, agility, or speed descriptor at the beginning of a combat. Actions proceed each round from highest roller to lowest.


One round is three seconds, give or take. In a round, a character can normally move about six meters and still have time to attack. If the character is running or sprinting, she can cover more ground, but her attacks are easier to avoid.

Table: Movement
Movement m/round km/hr
Walking 6 7
Running (defender gains 1d6) 12 14
Sprinting (defender gains 2d6) 36 42

If a descriptor increases a character's movement rate, add the rank of the descriptor to her walking speed and running speed. If she is sprinting, roll the number of dice in the descriptor, and add that to her sprinting speed. For example, if a character had three ranks in in "Olympic triathlete", she would walk 9 meters per round (or 10 km/hour), run 15 meters per round (or 18 km/hour), and would sprint 36 + 3d6 meters per round (or 42 + 3d6 km/hour).


An attacker may make one attack roll per round. Roll a combat, strength, agility, or similar descriptor. Compare it to the defender's roll. The attack is successful if the attacker's roll exceeds the defender's roll.


Roll a combat, agility, or similar descriptor. A defender may roll as many times as necessary, but each attacker after the first gains a +1 bonus to her die roll. For example, four exceptional attackers would roll 2d6, 2d6+1, 2d6+2, and 2d6+3.

Some situations provide a bonus to the defender's roll. Generally, only the best defense bonus applies.

Table: Situational modifiers
Situation Defense bonus
Partially covered 1d6
Mostly covered 2d6
Completely covered 3d6
Attacker running 1d6
Attacker sprinting 2d6
Thick fog 1d6
Darkness 2d6
Attacker blind 3d6
Defender dodging 2d6


On a successful hit, roll the dice indicated for the damage the weapon causes.

Some fringe descriptors may be used to increase the damage of an appropriate weapon. If so, the weapon's damage increases by 1 for each rank in the fringe descriptor. If a fringe descriptor itself is the "weapon", it may inflict up to 1d6 for each three ranks in the descriptor. Using a fringe descriptor in this fashion requires the expenditure of a point of fringe.

Table: Fringe damage bonuses
Fringe descriptor rank Bonus or Damage
1 Mundane 1 1d2
2 Exceptional 2 1d3
3 Elite 3 1d6
4 Heroic 4 1d6+1
5 Legendary 5 1 ½ d6
6 Mythic 6 2d6

Damage modifiers (optional)

Some weapons modify how much damage is caused, or how armor defends against it.


An exploding weapon causes its damage to everyone within skirmish range of the target.


Damage from a penetrating attack ignores 50% of armor protection value (round in defender's favor).


Damage from a stunning attack is temporary. Record it separately; it all comes back when the character recovers. Stunning attacks do not reduce armor integrity.


Subtract the protection value (PV) of the defender's armor from the attacker's weapon damage.

Some fringe descriptors may provide protection value instead of or in addition to conventional armor. If so, the fringe descriptor provides up to 1 PV for each rank in the descriptor. Using a fringe descriptor in this fashion requires the expenditure of a fringe point.

Armor integrity (optional)

Armor also has integrity. Subtract the damage absorbed by the armor from the armor's integrity. When the armor's integrity is reduced by 50%, its protection value is also reduced by 50% (round in the defender's favor). When the armor's integrity is reduced to zero, it no longer provides any protection. Stunning attacks do not reduce armor integrity.

Losing health

Subtract the damage that exceeds armor from the target's health points. If a character is at half health or below (round in the character's favor), any action they attempt is increased in difficulty by one level (from Mundane to Exceptional, from Heroic to Legendary, etc.), and any opponent they engage is granted a bonus die for purposes of attacking or defending against the wounded character. If at 0 health or below, the target is out of the fight. If at a level of health equal to the negative of their normal health points (e.g., -20 for a character with 20 health points), the character may be out of the game.

Unnamed characters

If an unnamed character takes 5 or more points of damage from an attack, that character is out of the fight. If an unnamed character takes less than 5 points of damage from an attack, they ignore the damage.

Recovering health

After a chance to rest and recuperate (maybe half an hour), an injured character recovers half the health they have lost. After that, injuries recover only with extended rest or with medical care.

Recovering fringe

After a chance to rest and recuperate (maybe half an hour), a character recovers half the fringe they have expended. After that, the character's fringe points recover only with extended rest or a good night's sleep.

Range bands

There are four basic ranges: skirmish, firefight, visual, and remote. Skirmish range is the distance that a character can cross in a single action and usually still have time to do something else (typically up to five meters). Firefight range is too far for most people to reach in one action, but is within range of most small arms and other ranged attacks (from around five meters to 100 meters or so). Visual range is too far away to hit reliably with most firearms, but is still within line of sight. A few weapons have even greater range, called "remote": these effectively have no maximum range.

Weapons have a range beyond which they are less useful. Attacking targets at more distant ranges is more difficult or impossible (at the GM's discretion). If the GM declares that the attack is possible, the defender gains a bonus die to their defense roll for each additional range band.

For example, if a character is being attacked by someone at visual range, and the attacker is using a pistol (which is normally useful up to firefight range), the defender would gain one bonus die to her defense roll.

Table: Range bands
Range Typical weapons
Skirmish Fist, foot, sword, whip, taser, thrown knife, thrown axe
Firefight Pistol, bow, crossbow, rifle, slingshot, shotgun, machinegun, fireball spell
Visual Sniper rifle, laser, trebuchet, antiaircraft gun, psychic blast
Remote Long-range artillery, guided missile, rocket, voodoo curse


A character's descriptors may improve with experience.

Gaining experience

Generally, the GM awards one experience point per worthwhile game session. On rare occasions the GM may award an extra point for outstanding role-playing, completion of a long-term goal, an ingenious player idea, and so on.

Adding and improving descriptors

If a player spends experience points (XP) to add or improve a character's descriptors, the character loses those experience points permanently.

  • Adding an additional die to a descriptor (or buying a die in a new descriptor) costs 5 experience points. If the descriptor is a fringe descriptor, this cost is doubled to 10 experience points.
  • A descriptor may not exceed the limits imposed by the setting's fiction level, even with experience.
  • Adding an additional die to the character's fate dice costs 5 experience points.
  • Increasing a character's health points costs 1 experience point for each additional health point.
  • Increasing a character's fringe points costs 2 experience points for each additional fringe point.


Each genre will have a list of equipment appropriate to that genre. These examples are merely a guideline.

Sample weapons

Table: Sample weapons
Weapon Range Damage
Unarmed combat Skirmish 1d2
Light thrown weapon Skirmish 1d2
Light melee weapon Skirmish 1d3
Heavy thrown weapon Skirmish 1d3
Medium melee weapon Skirmish 1d6
Heavy melee weapon Skirmish 1d6+1
Psiblade Skirmish 1d6 PEN
Hold-out blaster Skirmish 1d6
Stunner Skirmish 1d6 STN
Target blaster Firefight 1d6
Blaster pistol Firefight 1d6+1
Blaster carbine Firefight 1d6+1
Heavy blaster pistol Firefight 1 ½ d6
Heavy blaster carbine Firefight 1 ½ d6
Blaster rifle Firefight 2d6
Heavy blaster rifle Firefight 2d6+1
Wrist rocket Firefight 2d6 EXP
Frag grenade Firefight 3d6 EXP
  • PEN: Penetrating damage ignores 50% of armor protection value (round in defender's favor).
  • STN: Stunning damage is temporary. Record it separately; it all comes back when the character recovers.
  • EXP: Exploding damage causes injury to everyone within skirmish range of the target.

Sample armor

Table: Sample armor
Armor Protection Integrity
Thickly padded clothing 1 5
Trash can lid 1 5
Light leather 1 10
"Hubcap" armor 2 10
Wooden shield 2 30
Heavy leather 2 20
"Junk heap" armor 3 15
Padded heavy leather 3 30
Ballistic mesh clothing 3 45
Police riot shield 4 60
Personal force field 4 80
Chainmail bikini 4 20
Chain cuirass 5 50
Light metal shield 5 50
Light ceramic armor 6 60
Light polycarbide armor 6 90
Duelling force field 6 120
Plate metal armor 7 70
Heavy ceramic armor 7 105
Heavy metal shield 7 105
Dwarven plate armor 8 120
Heavy polycarbide armor 8 80
Assault force field 8 160
Stanlium armor 9 135
Servo-assisted armored exoskeleton 9 90
Dragon scale armor 10 100
Siegelite armor 10 150
Heavy assault force screen 10 200


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