Auto success and failures, rule of 19

[RobW]

Originally Posted by Skarg

Just always have 3 dice the same color, and use those dice only to determine the usual end results on 3 dice, with the other dice only mattering if you haven't rolled a 3-5 or 16-18.

But that's only good IF that is really what you want.

There's been some discussion in the main forum about critical failures. TFT LE has the new mechanic that chances of auto failure increase, quite dramatically, as you add dice to the roll for success.

The table on p9 of TFT LE tries to do two things as the number of dice increases: keep the odds of auto success about the same, and increase the odds of automatic failure

It's fine, but, I'm not wild about hunting things up in a table. And much more importantly, the 3D rolls have easily interpreted outcomes, eg auto-success, 2x and 3x damage. The larger rolls just don't have this. I instinctively know that on 3d6, 16 is bad, but 18 is really really bad. It even gives me license as GM to use my imagination when a critical comes up.

But if someone rolls a 8 against a dodging weapons master, is that really really bad, or just bad? I don't know.

So what I'm proposing is a variation of the colored dice idea above. Rolls for success always include 3 colored dice (the "critical dice") that are used to judge auto and critical success or failure. So on a difficult 5d roll, you would roll 5 dice, three of them are the "critical dice".

As normal, you add together all the dice and compare to the stat being checked. But the critical dice (only) are used to determine auto/critical success or failure.

The chances of auto and critical success never change as the dice increase, 5 on the critical dice means an auto success, regardless of the total on all dice. A 4 is success at the level of double damage; 3 is success at the level of triple damage. Same with critical failures: 17 on the critical dice is always a critical failure at the level of a dropped weapon; 18 is a critical failure at the level of broken weapon or backfired spell.

The chance of auto failure DO increase as the number of dice increases, according to the "rule of 19". If the sum of the critical dice + the total number of dice rolled >= 19, it's auto failure. For example, on an 8d roll for success, a roll of 11 on the critical dice is automatic failure (11 + 8 = 19, wahr wahr).

The next post will show how the rule of 19 compares to TFT p9