Just Another Game System (JAGS) is a univerals system. This overview is of the revised edition which is 270 pages in the pdf.

The rulebook lists some things which JAGS does well:

  • Scalability of Character: From gigantic monsters, to masters, to students.
  • Variance in Lethality: Characters can be though without being inhuman or they can be easily killed (or they can be inhuman).
  • Distinction of Character: A character that is very good at something is unlikely to be made obsolete by someone else who can do your thing better.
  • Lots of Special Abilities: Archetype system desgined to give characters cool special talents without a huge dictionary of abilities.

Character Creation

Balanced point buy system. No classes.

Primary Stats are physique, reflexes and intellect with averages of 10. Each primary stat has three secondary stats (equal to primary unless modified). These are strength, build and constitution for physique. Coordination, reaction speed and agility for reflexes. Reason, memory and willpower for intellect. Stat costs are listed in a table. A stat of 9 for example gives 5 points back to spend on other things, 10 zero, 11 costs 5 points, 12 costs 15, 13 costs 30 and so on. The secondary stat can be +2 or -2 from the primary, with the cost depending on the difference and given in a table. Only up to three secondary attributes can deviate from the primary and must be given a name when they do to describe why they deviate.

Traits are things that distinguish the character such as good looks and wealth.

Choosing skills takes four steps to determine if it is expensive or standard, mastery level, whether to link it to a stat and customisation (description of why skill is known that may give bonuses when applies to roll). The cost for the roll and and mastery level is determined from various tables depending on if it is expensive or not and if it is linked or not.

  • Character Points: CP are used to buy stats, skills and traits. Average person has 30, typical adventuerers 50 and experts 75.
  • Archetype Points: AP are used to buy unusual or genre-specific. Average person has 0-8, typical adventuerers 8 and experts 8-16.
  • Skills: Have a roll and a mastery level of 1 to 4 from beginner to master. The mastery level determines how the skill can be used. They have the option of being based on a stat or not. Skills can be expensive or standard cost to buy.
  • Distinction of Character referred to as niche protection tries to ensure that no role can be taken over by another (eg. a warrior cannot become a better spellcaster than a wizard). This is done with the Archetype Point system by only giving a limited pool of points to spend on special defining abilities.
  • Figured Stats: Based on secondary stats and traits these are base damage, charisma score, damage points (hitpoints), grapple score, ground speed, initiative, perception, wound & condition levels.

Task Resolution

4d6 (bell curve), where a 6 is treated as zero must be equal or less to the target number.

  • Skill/Stat Check: Roll under skill or stat (after modifiers).
  • Resisted Rolls: Contested roll where the winner is the one who was the furthest under his own target number.
  • Resisted Rolls with numbers: When numbers vs number (eg. armour save, grapple) are resolved by only one party rolling against a Target Number of 10 minus the resisting persons adjusted value. This adjusted value is the difference when the values are less than 20, but when above 20 both values must be divided by a set divisor between 5 and 75 as per a table.
  • Drama Rolls: Optional at any time, makes the task resolution more involved.
  • Degree of Success/Failure:
    • Minor: Equal to target number/one higher than target number
    • Major: 5 less/more than target number
    • Critical: 10 or less/more than target number
  • Failure: Several ways of handling it are discussed.
    • Asking the player what went wrong (and it doesn't have to be the character's fault).
    • A secondary task is required.
    • Something else went wrong
    • More time is needed
  • Success Points: Can be spent to remove negative modifiers before a roll or improve a success after a roll. Maximum of 2 can be spent on one roll.

Combat Resolution

One round is six seconds. A defensive move can interrupt an attack.

  • Wound Levels: Single wound effect. Sub-Minor to Critical (might kill you). A healthy, un-injured character can get knocked out by a single blow that does a Minor Wound if unlucky.
    • Sub-Minor: Less than 1/3rd total Damage Points (DP)
    • Minor: 1/3 to 1x Damage Points
    • Major: 1x up to 2x Damage Points
    • Critical: 2x or more Damage Points
  • Condition Level: Cumulative wound effect. Normal to Serious (fragile and in need of immediate medical attention).

Social Interaction


Character Development




Publishing Company

Marco Chacon



  • Marco Chacon


System Analysis

On a partial first reading the impression is that its quite rules heavy with a lot of tables, as well as some multiplications and divisions. The reward is that it seems fairly flexible, but I wonder if this does not also mean it would take some time to determine which rules would apply in a given setting.


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House Rules


Free PDF downloadable from the JAGS website. Also available in hardback from lulu.

An unmodified roll against a target number of 5 will succeed 9.75% of the time, against 10 55.7%, against 15 94.56% and against 20 100%.

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