In certain media, super powered individuals fire ranged energy attacks at each other. The attacks collide and push against each other until one attack successfully breaks through. Today’s post contains two ways to model this situation - one of which may be novel.

Power Parry

One way to model this situation in GURPS is to use Power Parry rules from Powers pp. 167-168:

  1. Alice attacks Bob with some Innate Attack type ability
  2. Bob defends with a Power Parry using some suitable Innate Attack type ability
  3. If Bob succeeds (and blocks all damage), Bob attacks
  4. Alice defends
  5. Repeat until one person’s attack get “gets through” the other’s defense.

One benefit to this approach is that it adds no new rules. Everything is already covered by the rules in the Basic Set and the additional Power Parry rules in Powers. It also resolves the situation in only a few rolls.

A disadvantage to the approach is that it may resolve the situation too quickly. It is unlikely that all damage will be prevented for long. Also, in some media, the loser often takes the full force of the attack on a loss. This only happens when the parry fails entirely.

A slightly modified approach solve partly solves the problem. Simply continue until a defense fails entirely. Alice and Bob may both be injured in this exchange, but that may be desirable.

Beam Contest

Another idea is to use contest mechanics.

These rules are designed with the following constraints in mind:

  • Attacks are vaguely “beam-like” ranged or jet attacks
  • Opposing attacks are of the same or opposing powers or otherwise follow the guidelines from the Power Parry rules
  • Attacks are converted to numeric values suitable for use in contests

Converting attacks to values appropriate for contests require a bit of prep work:

  1. Optional: scale the damage dice to an appropriate scale (e.g. scale 150d damage to 15d D-scale damage) using the rules from B470
  2. Convert the damage dice to a number by reversing Modifying Dice + Adds B267
  3. Optional: apply the Extreme Scores (B349) if using a Regular Contest

I am not sure if both optional scalings are useful or necessary. One may be enough, but both may be useful in some circumstances. Try both and see what works best.

Examples

Below are some examples of using beam contest rules to resolve opposed beam attacks. In both cases Alice and Bob both have 10d beam type attacks. This results in a contest value of 35 or (10 if scaled using the Extreme Scores rule).

Quick Contest (QC)

  1. Alice attacks Bob
  2. Bob defends with a Power Parry using the normal defense roll and succeeds
  3. Instead of rolling damage, Alice and Bob make a QC a. Alice rolls a 9 for a success by 26 b. Bob rolls a 13 for a success by 22
  4. Since Alice won the contest, Bob takes the full 10d damage from the attack for a total 26 damage

Since this example used a QC, it was not necessary to apply the Extreme Scores rule.

Regular Contest

  1. Alice attacks Bob
  2. Bob defends with a Power Parry and succeeds
  3. Alice and Bob initiate a Regular Contest a. Alice rolls 10 for a success b. Bob also rolls 10 c. Alice rolls 5 for a success d. Bob rolls 9 for a success e. Alice rolls 11 for a failure f. Bob rolls a 5 for a success, winning the contest
  4. Since Bob won this contest, Alice takes the full 10d damage from the attack for a total of 43 damage

Since the example used a Regular Contest, the contest would have taken much longer without applying the Extreme Scores rule.

Options

The approach listed above is half baked, so here are some optional ingredients that you can add and finish the job.

Fatigue Cost

Beam contests can be fatiguing. If the underlying attacks already cost fatigue, perhaps that is enough. If characters use Extra Effort with their attacks, that may also be enough. If characters regularly engage in beam contests using attacks that don’t cost any fatigue, consider charging a point for any contest.

Alternate Initiation

Perhaps you don’t want beam contests on every parry or think that it gives the defender an unfair possibility of counterattack. Perhaps you want to save the beam contest for special occasions. Dealing with the unfair counterattack is simple. Rule that a engaging in a beam contest uses the defender’s action. For the other concerns, a few options are presented below:

  • Require the defender to make a wait maneuver to engage in a beam contest if the attacker uses a beam
    • You may even skip the active defense in this case and rule that it requires a simple successful attack or the “defender” succeeds in engaging in a contest automatically
  • Borrow the rules for Contest of Wills (Martial Arts p. 130) except that the Will roll is to avoid being drawn into a beam contest
    • This can justify beam contests when dodging would be the sensible choice

Non Beam Contests

Nothing about these rules requires that they be restricted to beams. They simply happen to be common. Hands, swords and dangerous beasts made of projected chi are not particularly uncommon. Feel free to use these rules for non beams if you wish.

Strong supers may be able to contest beams with their strength and endurance. In this case, use the brick’s thr, punch or even slam damage in the beam contest. If the brick wins, he successfully punches, slams or otherwise physically attacks the beam user.

It may work for Affliction and Binding. For Affliction vs Affliction or Binding vs Binding, you can use the levels directly instead of trying to convert to damage. For Affliction or Binding vs a damaging attack or Affliction vs Binding, use the rules from Powers p. 168 to convert to equivalent damage dice.

It might also work for Telekinesis, but consider using Technical Grappling or the more streamlined Fantastic Dungeon Grappling for TK vs. TK contests. For using Telekinesis against some other attack, use the thrust damage based on the TK’s ST.

Partial Damage

Perhaps you want to use beam contest rules but want only some damage to get through. One way to accomplish that is to allow partial damage based on margin of success/failure. Consider the following:

  • On a tie, no damage gets through.
  • On a success by 5+, all damage gets through
  • Pick some ratios in between for other degrees of success

This option is easiest when using the Quick Contest resolution.

Design Notes

I haven’t actually used any of these rules since I’ve not had the opportunity. Most of the rules are based on existing, well used mechanics, so they should work fairly with a bit of customization. Your millage may vary.

The material presented here is my original creation, intended for use with the GURPS system from Steve Jackson Games. This material is not official and is not endorsed by Steve Jackson Games.