Friday, February 17, 2012

3d6 Combat System

Here it is, my first draft (at least the first one I've wanted to present) of a 3d6 combat system. While Searchers of the Unknown inspired me to do this, it has become more of its own thing. It is still my hope to condense everything down to one page, but once I started this and the ideas started flowing, the one-page thing became less of a priority. I'll worry about page count when I get it hammered out. Without further ado . . .

Basically, I want to have the to-hit roll target be the opponent's AC (per SotU), roll under on 3d6. Modifiers (please remember that this is roll under so a negative modifier is a Good Thing):
Character Type Bonus
Burly -1/2 Levels
Cunning -1/3 Levels

Magician -1/5 Levels

Damage will be determined by the degree of success of the to-hit roll:
Simple Success (RollAC) deals 1D
Great Success (RollAC-2) deals 2D
Stunning Success (RollAC-4) deals 3D

In all cases, the damage die is d6. In the case of multiple dice, only like numbers are considered, with the highest being totalled. Light weapons are -1 to all dice counted, Medium weapons are unmodified, and Heavy weapons are +1 to all dice counted.

So, how about some percentages?

A 1st level Burly Adventurer vs Opponent in Chain (AC6)
Level +1
Opp. AC +6
Roll Needed 13
Chance to-hit 40%
Level -1
Target 6
Roll Needed 7
Chance to-hit 16%

So, obviously something needs to be done here. Bearing in mind that the roll “to-hit” is more accurately described as a roll “to-damage”, we can explore the following. Historically maces were brought to bear against opponents in metal armors. They didn't damage the opponent by penetrating the armor, they wore the opponent down by knocking him around inside the armor. Sooooo . . . what if we apply the following:
Metal armors (Chain and Plate) are +2 vs bludgeoning weapons. Then we get the following chance to-hit:
Level -1
Target 8 (AC6 +2vs Mace)
Roll Needed 9
Chance to-hit 37.5%

That is much more in line with the other numbers. It has the added option of providing a layer of tactical choice at a small complexity premium. To offset the beneficial to-hit, as well as maintaining a degree of accuracy, damage degrees are calculated without the modifier. Thus, the damage degrees for the above scenario would be:
Original unmodified AC 6
Roll needed for Simple Damage (1D) ≥9 (37.5%)
Roll needed for Great Damage (2D) 4 (1.9%)
Roll needed for Stunning Damage (3D) 2 (0%)

Ok, that's all done considering a 1st level adventurer. I believe the numbers will hold up because after you reach a target number of 10 on 3d6, the bonuses hit a law of diminishing returns. Also, there is the fact that, in all truth, I was forced to device this so that low level characters can have any hope against heavily armored foes. Still and all, though, it seems reasonable to me, and at least gives a nod to accurately modeling the effects of bludgeoning weapons against metal armors, insofar as the system I am presenting.

Thoughts, comments, criticisms?

PS> The percentages above were arrived at using the Dice Probability Calculator link at the bottom of my Hall of the Sages column at left.


  1. I made a 3d6 system a while back, which you might find interesting:

  2. Thanks, Simon. I picked up so many followers all at once the other day, I haven't had the chance to see how many of you have blogs and so forth. Yours looks pretty damn cool. I've added it to my Halls of the Sages column. I like what you've done with characteristics; the names, what they represent, and how they combine. I haven't read the rest yet, just wanted to say thanks for the link.