Yesterday’s resolution of a never-ending argument seemed to go down well, you know, barring a few outliers who seem to want to keep discussing the topic as if there isn’t one perfect answer right there… Anyway, here’s another never-ending argument resolved!
Roll-under Or Roll-over
Some people like to roll their dice and add their bonuses to try and meet or beat a target number. This is fine and it works but you are adding all these little numbers and don’t those targets feel a little arbitrary? DC15, TN 25, Difficulty 8. What does that even mean!?
Others prefer roll-under, which has the advantage that the default difficulty is right there on your sheet. Roll-under RPGs do have all sorts of weird and wonderful ways of messing up this beautiful simplicity as they apply difficulty modifiers though. And don’t get me started on opposed rolls TOO LATE I played in a GURPS game once where every attack was opposed so we had to deduct every successful roll from our skill to get our margin of success while the GM did the same with their NPCs’ defense rolls, we then had to compare these margins of success to see if our successful rolls were actually successful. Proponents of roll-under will tell you that it is “more intuitive”.
Surely there is a better way?
The Better Way – R.U.B.
Roll-under blackjack is the solution to all these problems. It is simply this: Roll under your stat/skill score to pass, the higher you roll the better.
So if your stat is 13 your potential successes are 1 through 13. If you are rolling a skill of 8, you could pass with a 1 through 8. It’s basically the same ranges for margin of success that you would have reached with a bit of maths in standard roll-under, but we’ve skipped the maths. Similarly we don’t need the maths used in roll-high because your Stat or Skill or whatever *is* the target number.
Even when applying varying difficulties you don’t need maths, just make it a minimum successful roll. Say you are rolling an d100 engineering test with a skill of 70, your GM applies a 25% difficulty to the check, so now you pass if you roll 26-70. Quick simple intuitive.
Is there a catch? Honestly, not really. It only works with linear dice rolls, things get weird when you add bell curves into the mix, but that’s fine, linear dice are better anyway (spoilars!). Also there isn’t a mathless way to make checks easier but that’s fine too, just don’t make your players roll for easy tests.
Credit where it’s due, RUB has been around since the 90s. I first encountered it in Fading Suns and in Unknown Armies. These days Whitehack and Mothership both make excellent use of it.
Tomorrow I might justify my wild assertion that liner dice rolls are best.
Maybe.
Ominosity 