Rules v1.2.1

Dice System

As in many other tabletop miniature wargames, Jovian Wars uses dice to determine the success or failure of an attempted action on the table. Jovian Wars terms these attempts Tests or Rolls. For example, you might be asked to perform an "attack roll" or "skill test."

Jovian Wars uses a system of rolling a pool of six-sided dice to determine the Result of Test or Roll during gameplay. Generally, rolling a pool of X dice is represented as Xd6, i.e. rolling two dice would be represented by 2d6.

A successful Result in Jovian Wars involves having at least one set of matching die faces. For example, if you roll 2d6 and get the result 2, 2 that is a success as there are matching dice! A Result of 2,3 is considered a failure as no die faces match. There are degrees of success as well.

The more die faces that match, the higher the degree of success, i.e. rolling three 3's is better than rolling two 3's. As a written shorthand for the result of a dice roll, we use the following notation where the result is enclosed in square brackets:

  • [N] - No Result - This represents rolling all unique die faces, i.e. no matches, and is considered a failure.
  • [D] - Double - Success, with two of the dice matching.
  • [T] - Triple - Success, with three of the dice matching.
  • [Q+] - Quadruple - Success, with four or more of the dice matching.

Adding a "+" to the notation is a way of denoting a minimum level of success. For example, a [T+] means that any result equal to or better than a Triple is successful. Quadruples are the highest level of success--getting five or more matching dice does not improve the level of success.

The actual die face rolled is often important also. If you roll two 2's, that is a double 2, and is denoted as [D2]. You could also roll multiple matching sets! A result of [D2,D4] means you rolled two 2's, two 4's, and the rest of the dice have no matches.

Here are some examples:

  • Example 1: A 3d6 roll results in 1, 4, 5. The result is [N], no sets/successes.
  • Example 2: A 3d6 roll results in 2, 2, 4. The result is [D], a double. The result could also be written as [D2] to show that a double was rolled and it has a value of 2.
  • Example 3: A 5D6 roll results in 1, 1, 3, 3, 3. The result is a [D] and a [T], a double and a triple. The result could also be written as [D,T], [D1,T3], or even [D1,D3+].


A Re-Roll in Jovian Wars consists of performing a roll from the beginning of the procedure in its entirety. This means calculating the Base Pool, Flex Dice, and Macro Pool again, and re-rolling all of the dice together.

In practice, this is as simple as picking up all the dice again and re-rolling them, being sure to add back any Flex Dice that were removed.

You may only re-roll once, even if multiple effects would generate multiple re-rolls.


In some cases, you will be asked to Esclate a successful Result, i.e. increase the magnitude of the success.

  • The value of the Result will remain the same.
  • You may not escalate a No Result [N] into a Double [D].
  • A [Q+] Result remains a [Q+] result.

Example: Dave fires a Nuke at a Capital Ship, and rolls a [D2]. The Nuke rules say to Escalate Attack Rolls, so Dave's [D2] result becomes a [T2] result.


In somce cases, you will be asked to Diminish a successful Result, i.e. decrease the magnitude of the success.

  • The value of the Result will remain the same.
  • Unlike Escalation, you may Diminish a [D] to an [N].
  • The value of the attack remains the same.
  • Regardless of how many faces match, a [Q+] result diminishes to a [T] result, e.g. even if you rolled 6d6 and got six 2's, that [Q2+] becomes a [T2].

Example: Dave uses the Long Range Sensors Special Action to target a Capital Ship outside his sensor range. He rolls a [T4], but the Long Range Sensors Special Action requires you to Diminish your results, the final result is a [D4]. Had Dave rolled a [D4] initially, he would have Diminished it to a [N], and his shot would have missed.

Skill Test

Occasionally you will be asked to make a Skill Test against a model's Skill rating or in some cases a System rating, e.g. against Sensors. Make a roll using the appropriate rating as the number of dice in the Base Pool.

Calculate the Result as above. The rule prompting you to make a Skill Test will codify the meaning of the results.

Some actions may allow a model to roll using the rating of an attribute instead of the skill rating.