1 - The Dice

At its core, this game system is built around three six-sided dice (3d6), typically rolled and added together. Such a roll is called a test. The target number is 10, though the roll itself is adjusted with modifiers, which may come from stats, skills, gear, and/or situational modifiers. With no modifiers, a roll of 10 or more on 3d6 has a 62.5% chance of success.

When a test is made, 3d6 is rolled, modifiers are applied to the result, and 10 is subtracted from the total. If the result is a negative number, the roll is a failure, while zero or more is a success. The degree to which a success or failure is rolled can have an impact on the results. Each time a check is made, the person making the check must announce their results in the following way. If a total roll is zero, that is a Success of Zero, and represents the bare minimum success, with positive numbers giving a Success of [number], with the number being how much above zero was rolled. For example, for a roll of 12 (including modifiers), this would be announced as a Success of Two. For failures, the reverse is true. So, if a 9 was rolled (with modifiers), that would be a Failure of One, while a roll of 7 against the same target would be a Failure of Three.

Rounding down: sometimes you have to divide a bonus by a fraction, such as half (1/2). Whenever you end up with a fraction, always round down to the next whole number.

Criticals and Blunders: a natural 16, 17, or 18 has a combined probability of only 4.6%, as does a natural 3, 4, or 5. These rolls rarely happen as a result. If a natural 16, 17, or 18 is rolled, this is called a critical. If a natural 3, 4, or 5 is rolled, this is called a blunder. A critical gets a bonus to the roll, allowing higher totals than is possible on a 3d6 (18 maximum, 3 minimum), and vice versa for blunders (the final result of the blunder may be a negative number).
Depending on the critical/blunder, roll additional dice and add them to the result.

Natural 18 = +3d6
Natural 17 = +2d6
Natural 16 = +1d6
Natural 5 = -1d6
Natural 4 = -2d6
Natural 3 = -3d6

Chaos: when rolling a check, if three dice roll the same number, such as three twos or three sixes, this triggers a chaos result - something chaotic has happened and the GM must roll again to determine the chaos result. Slightly less than 2% of rolls will have chaos effects, so they are rare - the GM should use such an opportunity to add a memorable, chaotic complication to the action. To check the chaos result, the GM rolls 3d6: high is beneficial, low is harmful, determined by the GM. Possibly compare to 10, halving the difference, and use the result as a temporary modifier for one round. Note that the chances of a chaos result increase with Superior or Inferior checks (see below), as only three dice need to hit the same number.

Test:
Skill (or Stat) + modifiers
10 or more = Success of (number above 10)
9 or less = Failure of (number below 10)

Tiers of Difficulty

Sizes play an important role in this system, from weapons to opponents, and it brings a mentality of scale to the system. For each smaller size category, for example, attacks do an additional 1d6, while versus larger targets lose 1d6 per size category. For successes on attack rolls, each Success of Three is converted to +1d6. Three is a number to track scaling damage, as each Success of Three scale the damage up one size. A similar philosophy can be used with the difficulty, you can think of each +3 to be a different tier, a larger size if you will, of the ease or challenge. This may help gauge the difficulty of a test, and may also help to gauge the "tier" of abilities employed to win that test:

• Trivial (+9 test) - would be very unlucky to fail and likely to score high successes, with roughly a 99% chance of success.

• Professional (+6 test) - unlucky to fail and likely to score several successes, with roughly a 98% chance of success.

• Easy (+3 test) - odds are still good, likely to score a few successes, with roughly a 90% chance of success.

• Uncertain (+0 test) - odds slightly in favor but success and failure feels like a coin toss, with roughly a 62% chance of success.

• Hard (-3 test) - odds are not good, likely to score a few failures. with roughly a 26% chance of success.

• Clueless (-6 test) - unlikely to succeed and likely to score several failure, with roughly a 5% chance of success.

• Hopeless (-9 test) - would be very lucky to succeed and likely to score high failures, with roughly a 3% chance of success.

For example, attempting a hard test untrained can be a tough gamble (test -3), but for someone with positive modifiers (such as ranks from a skill or stat bonuses), a +3 (one higher tier) would bring it to -3+3 = 0 (Uncertain), while a +6 (two higher tiers) professional treats that hard test as Easy (-3+6 = 3, Easy).

Extended Test

When a test involves an activity that's prolonged, such as forging a weapon or running for hours, an Extended Test is used. These may have modifiers to the test and a Threshold, which sets the number of successes needed to complete the task (or the number of failures to fail it). Each roll represents a period of time engaged in the activity, determined by the GM. For crafting, for example, most extended craft tests take about an hour of work per roll. With each roll of an extended test, keep track of the number of successes and failures rolled. Blunders (where failures hit threshold and there are no successes) are the worst type of failures, hitting the failure threshold is also a failure (perhaps not as bad as a blunder), while hitting the threshold with successes is a success (perfect if no failures).

extended Test:
Skill (or Stat) + modifiers
Threshold = number of successes/failures to succeed/fail
Failures hit Threshold (no successes): total failure, may impose additional consequences
Failures hit Threshold: failure
Successes hit Threshold: success, failures impact degree of success
Threshold with no Failures: perfect success

Example: say a character is sailing a small boat across a grand lake, an all-day affair to reach the far shore, and a strong storm is approaching from behind. They race the storm, trying to reach the far shore before the storm overtakes them, for the boat is too small and flimsy to handle the winds without capsizing. The GM decides this will be a sailing extended test, Threshold 10, with a -3 penalty. The character has a skill of +4, so they make the extended sail test with a +1. Let's say they get nine successes before they hit the threshold for failures. Since they were 9/10 successes, the GM determines the storm caught up with them 90% of the way across and capsizes their boat. Now he asks for an extended swim test to reach the shore...

Superior and Inferior Test

Sometimes the odds are stacked for or against your test, depending on the circumstances. Extreme situations, where factors lead to substantial help (or hindrance), a Superior or Inferior Test may be more appropriate than simple bonuses or penalties. Superior checks skew towards criticals, while Inferior ones skew towards blunders.

For such tests, extra dice are added to the base roll of 3d6, then either the best or worst three dice are used to tally the result. Superior tests take the highest three, while inferior tests take the lowest three. The more extreme a situation, the more dice added. For example, sneaking up to someone and attacking them when they don't notice you may result in a Superior 1 Test (3d6+1d6, take 3 highest), while using a knife held to the throat of a restrained foe may result in a Superior 2 Test (3d6+2d6, take 3 highest). Some counter-examples: attacking a foe with a melee weapon while another is grappling you could result in an Inferior 1 Test (+1d6, take 3 lowest) while attempting to hit a target with a thrown knife that is two range categories beyond its listed range is an Inferior 2 Test (+2d6, take 3 lowest).

If multiple circumstances affect the odds, such as multiple superior or inferior modifiers, add like modifiers and subtract different ones. For example two circumstances that each give a Superior +1 would combine to give you a Superior 2 Test, while having a Superior +1 combined with an Inferior +2 would result in an Inferior 1 Test.

Below are the probabilities when rolling 4d6 and taking the lowest/highest three results. Notice that, for a Superior I Test, the bell curve is skewed towards the higher end, with the chance of a good critical increasing to 13% while a bad critical drops to 1.2%, while for an Inferior I Test the chance of a good critical is only 1.2% while a bad critical increases to 13% (Superior/Inferior are mirror opposites). This skewing of good/bad results across the bell curve increases with 5d6, 6d6, etc., as an example the odds of 5d6 is shown at the bottom (good crits for Superior 2 are nearly one in four, while bad crits are only three in a thousand. For Inferior 2, switch the good/bad odds). At Superior/Inferior 3 or more, the bad/good crit chance is effectively zero.

Below is a table of the probabilities of blunders from inferior tests (result of 3, 4, or 5), and the overall chance of a critical (range 16 to 18); as well as the probabilities for criticals from superior tests (result of 18, 17, or 16), and the overall chance of a blunder (range 18 to 16). Note for Superior/Inferior 3 or higher, the chances of a blunder/critical are effectively 0 (less than one in a thousand).