What is the general feeling about “roll under” as opposed to “roll over”?

For instance, in B/X a 5th-level fighter needs an 11 or better to hit an opponent in chain mail (AC5). That is 10 results out of a possible 20 on a d20.

What if the fighter’s player needs to roll a 10 or less on 1d20 instead of an 11 or more?

To-hit rolls and saving throws, among many things, are typically “roll HIGH to succeed.” But some other things, such as d00 percentile rolls and 1-in-6 listening checks, are “roll LOW to succeed.”

I don’t know how many games (other than d00-based games) use a roll low to hit system. Would anyone have a problem if all game mechanics in a fantasy RPG were changed to “lower is better”? Has there been any serious discussion of this somewhere?

18 Comments to “Roll Low To Hit”

  1. Jeff Rients says:

    I maintain that people generally like rolling righ numbers.

    • Kilgore says:

      I agree, and my son is opposed to the idea of rolling low to hit.

      But he’s got no beef with roll under DEX to avoid falling into a pit or 1-in-6 chance to hear noise.

  2. Staples says:

    I don’t have a problem with it personally, and often ask my players to roll under their stats to try certain things. They seem to line up with what Jeff said, though- they really didn’t like it when I tried to switch winning initiative rolls from higher number to lower number. I’m not sure there’s any real logical reason to prefer higher numbers, but RPGs aren’t only about logic, and, emotionally, it probably feels better to get rewarded or be successful when rolling higher numbers.

  3. J.D. Higgins says:

    In my B/X and Engines & Empires games, I’ve generally converted every manner of “task resolution” to a roll low system. Skills are “roll your rank or lower on 1d6”; characters’ saving throw numbers start at (7 + Wis mod) and go up as they level, requiring players to roll under the number on 1d20 to save; for turning undead, I converted the chart from “roll high on 2d6” to “roll low on 1d12”; and for attack rolls, the target’s AC plus the attacker’s to-hit bonus indicates the chance-in-20 to hit, with a natural 1 (an “ace”) indicating a critical hit.

    Essentially, every roll made to see “whether it happens or not” is expressed as “chance X in Y,” so that the players know intuitively to roll X or lower on 1dY. Players want to roll high when the dice are used to determine the *results* of their actions, e.g. weapon and spell damage rolls, hit dice of undead turned, that sort of thing. It might have been a little unusual at first for players who were just used to rolling high for everything (especially since many of my players were only previously familiar with the d20 System — I ref a campaign at my FLGS), but after about one session every new player always gets the hang of things. And most of them quickly come to prefer the simple addition of “descending AC + attack bonus,” which is actually really very intuitive. Pretty much anybody can grasp, without even thinking, “My fighter with Hit +3, attacking the ogre with AC 5, has a 40% chance to hit.”

    • Kilgore says:

      Essentially, every roll made to see “whether it happens or not” is expressed as “chance X in Y,” so that the players know intuitively to roll X or lower on 1dY. Players want to roll high when the dice are used to determine the *results* of their actions, e.g. weapon and spell damage rolls, hit dice of undead turned, that sort of thing.

      This is EXACTLY the way I’m thinking of doing it. Always roll low to try to succeed, roll high for level of success if you do.

      A number of the guys who would potentially play this game have never played RPGs before, so they wouldn’t be coming in with too much in they way of pre-conceived notions.

  4. I’ve been messing around with a mechanic I picked up from Infinity in which attacks are always roll low. The key to this mechanic is that when in melee you need to roll higher than your opponent if both sides are successful.

    I like it, but it eliminates the need for AC I think, which means messing with DRs and such.

  5. I would agree with the general statements here.

    If you are talking probability – 1 in 6, 47%, etc. – it’s roll-under.

    If you are talking reaching a threshold – hit AC 3 – it’s roll-over.

    If you are talking about opposed rolls it’s roll-over.

  6. Gratuitous Saxon Violence says:

    2d6 =< AC was the method back in the mists of time.

  7. Robin Ashe says:

    I generally prefer roll low, as it’s player empowering. The player knows whether they succeed, and can say “I hit” or “I miss”, rather than, “dose a 17 hit?” if you’re rolling high vs a target number.

    I particularly like Alternity’s situation die steps, where the GM would say what the situation die step bonus or penalty is, and you add or subtract the roll, thereby still leaving success in the hands of the player.

    You could have AC giving a +1, +2 or +3 step penalty, and other situations such as darkness or elevation could increase (or decrease if the PC is higher) that step. The step determines the die rolled in combination with the d20, so you’d roll d20+d6 if the step penalty is +2, and would have to roll under your relevant ability adding both dice. If you’re invisible or can see in the dark, it could be something like a -2 bonus because it’s easy and you end up rolling d20-d6, greatly increasing your chance of success.

  8. Cygnus says:

    I think it’s quite fun and natural to have some things be roll-low and some things be roll-high… but it helps when the dice are distinct. I’m using 1d20 for roll-high “to-hit” type things (including spell casting success or failure), and Xd6 (where X goes up with difficulty) for roll-low skill checks and saving throws.

    Logical? Probably not! But variety is the spice of life. 🙂

  9. Timeshadows says:

    I’ve moved everything to Roll-High.

    Also, I cannot think of anything in Traveller that requires a Roll-Low.
    –Instead of rolling Low on a stat, assign a DM to the roll and Roll-High, etc.

    • Kilgore says:

      In your U:WoM? Or in other games? I was trying to remember how you were doing it in your game.

      As far as “I cannot think of anything in Traveller that requires a Roll-Low” I should be clear and state right up front that this is NOT going to be Fantasy Traveller, though I know that’s what a lot of people are wishing would come to be.

      I’m not one of those wishers, though I do think there is probably a lot of potential there. We’ve got too much invested in our system to drop it. Someone else should do it.

      FWIW, this is going to use the standard D&D dice, not d6 only.

      • Timeshadows says:

        1). Yes, in UWoM. 😀

        2). I realised that my phrasing was poor after the fact. I am not assuming that your game system is fantasy Traveller, but enough of what you have posted suggested that sort of mechanical ‘vibe’, and I was merely stating based on that perceived vibe.
        –To answer the original question: Villains & Vigilantes uses a Roll-Low To-Hit mechanism.

        3). I am indifferent.

        4). Polyhedrals make folks feel like they are ‘getting their money’s-worth’. 😀

        I apologise for the previous, sloppy comment. :-/

        • Kilgore says:

          1) Cool. That’s what I thought but couldn’t remember for sure. Need to look it over again.

          2) Yah, very much the ‘vibe’, at least for character creation. Lots of the rest will be quite different, I’m thinking. Or maybe not so much. Still real nebulous at this point.

          3) I certainly think it would be cool, and when I was a kid I wanted to make it myself. I was going to do magic like psionics, which someone else here suggested. In the past couple of decades my tastes have changed a wee bit.

          4) That’s what I think, as well.

          No need for an apology. I really appreciate the feedback, especially from those like you who are working on their own system that’s trying to retain the ‘vibe’ of the old games while pushing (or breaking) limits.

  10. […] after discussion, reflection, and some playtesting, we’ve decided not to go with Roll Low to Hit in our suddenly-changing Wizards & Warriors homebrew. This decision means we will likely go […]

  11. Bombshelter13 says:

    Please don’t use a ‘core mechanic’.

    An aversion to core mechanics is probably why a lot of people like retrogames, clones, and games inspired by them.

    • Kilgore says:

      I think you might be right, and I think I do have an “aversion to core mechanics” as I noted in my follow-up post where we’ve decided to go with roll high on d20 to hit.

      However, even though I think you might be right and I might agree with the sentiment, I don’t quite understand it.

      Why is a “core mechanic” a bad thing?

      AD&D used roll high on d20 to succeed for to-hit, saving throws, and turning undead, probably three of the most common rolls success rolls, but no one whined. And it used 1-in-6 or 2-in-6 for many other checks.

      I’m not trying to be argumentative…I’m genuinely curious about the “aversion to core mechanics,” even though I have it. I’ve never played a game newer than 2e AD&D or MegaTraveller, and very little of either of those. Everything else is older, not counting retro-clones; and the retro-clone replicate older systems, as well.

      So it’s not personal animosity toward 3e or the piles of D20 stuff. And I’m not sure I would have been opposed to a D20 core mechanic back in the day.

      Have I picked up a bias from spending time on oldschool blogs and forums?

      Now that I’m thinking of this, I’m finding it strange.

      • Cygnus says:

        I think with “core mechanics” there’s a one-size-fits-all vibe that can develop. This seems to have hit its ultimate state in 4e (which I admit I’ve never played!), in which spells, fighting maneuvers, thief skills, ranger tracking, etc., are all handled in exactly the same way. Boring, yes, but it also implies there’s really no difference between the classes.

        In other words, once you open the door with a core mechanic, then it’s hard to stop a mindset of “game balance uber alles” from rushing in! 🙂

        All IMHO of course!