1 - Mechanics

#mechanics
The system is based upon the bell curve created by rolling 2d6, called Taking the Measure. The impetus behind this was trying to model success and failure as a window, including misses both above and below the target, and then I thought about craps. Ignoring 11 and the point system, the goal in craps is to roll a 7, which appears in 16.67% of all rolls and is the single most likely result on 2d6. 6 and 8 are the next most likely, then 5 and 9, 4 and 10, 3 and 11, with 2 and 12 the least likely. It's a pretty steep drop off.

7 = 16.67
6 or 8 = 13.89
5 or 9 = 11.11
4 or 10 = 8.33
3 or 11 = 5.56
2 or 12 = 2.78

So then I thought about what happens if instead of a flat bonus to hit and using Apocalypse World's 2d6 + stat vs a goal of 10+, what if the goal was just to get more consistent at hitting. Instead of adding modifiers to the roll, increasing a stat widens the character’s window of success around the central 7.

A character with a success window of 6 - 7 succeeds 30.56% of the time.
13.89 + 16.67 = 30.56

A 6 - 8 success window makes it 44.45.

A 5 - 8 success window, which represents a +2 widening of the window, produces a 55.56% success rate, roughly comparable to needing an 11+ on a d20 roll. The difference is distribution. A d20 has flat probability, where every result has an equal 5% chance of occurring. The Measure system clusters results around 7, creating more consistency, fewer extreme outcomes, and a much stronger sense of momentum and composure under pressure.

Because success is centered rather than thresholded, failure can occur on either side of the target. Rolling too low may represent hesitation, poor timing, or lack of commitment, while rolling too high may represent overextension, recklessness, or loss of control.

We can further modify that to have not just hits and misses, but also incorporated graduated successes.

Rule of 7 - A 7 always hits. We call it The Rule of 7. It's like a critical hit in D&D, except it doesn't double damage or whatever. It just does damage straight to the HP (or the Nerve).

Fumble - A 2 or a 12 is always a miss, called a Fumble. Fumbles always carry States with them.

Window - The target numbers you're rolling for are called your window. The base window starts at 7 for everyone.

Ability Bonus - For each bonus to an ability, the window when rolling that ability opens 1. Abilities can never go above +2.

Hit - Rolling anything inside window counts as a hit, remembering that 7s are special.

Complication - If you miss your window by 1 in either direction, that's a complication and in general you have a choice. You can hit and also take a repercussion, or you can choose to pull back into a miss. If you go through, you've accepted a risky opening to get a hit. Those repercussions may be traded damage or losing your footing or other potential repercussions (more on that later). Or, if you pull back, that represents your knowledge of the opening you would leave if you committed, and instead you deliberately pull back so as to not open yourself.

Miss - If you miss your window by 2 or more (except 2 or 12 - more on those in a bit), that's a miss. You recognize at the moment of the swing that what you were aiming for has either been covered up, or wasn't really an opening to begin with, but you can't recover in time, and suffer a repercussion. The standard repercussion is being Off-Balance, which widens the attack window your opponents are aiming for by 1. Skill trees can alter those repercussions, which are detailed elsewhere.

Fumble - If you roll a 2 or a 12, that's a Fumble. If you rolled high, you overcommitted to the attempt and cannot pull back in time, opening yourself to States. The standard repercussion for a Fumble is being Exposed, which turns all Complications into regular hits. Skill trees can alter those repercussions, which are detailed elsewhere.