Friday, 18 November 2011

Rapid Fire- Killing Two Rolls with One Stone

One easy way to speed up the game, or any game, is by not rolling dice. We could just compare attack and defense and have it automatically hit or miss without any variation. Blech!

Rolling dice is fun. We all remember those natural 1s and 20s that come up at crucial junctures in the game. Rolling is fun. Lots and lots and lots of fun.

Now what if I told you that to make the game more fun, I wanted you to roll 3d20 and add them up for your attack roll. I'll even it out by adding 21 to the defence of all the monsters you meet. This way the odds will be the same as before, but now we get to roll more dice!!! Would that make the game more fun? Is more the merrier the motto when dice rolling is involved?

If you're thinking "Hell yes! Now I can use my one die per finger rolling method every second of the game," then please stop reading. I have nothing for you.

For everyone else, you are unwittingly doing this in most games you play anyway. Rolling double the amount of dice you need for the same results. You may know it by another name: opposed checks.

Opposed checks involve you rolling the die and adding a skill, like stealth, and your opponent rolling a die and adding a skill, like perception. The highest roll wins the contest. But why do we do this? We don't do it for any other contest. We don't roll a d20 and add it to our AC when defending against the attack roll. Skill DCs are set values, they don't vary by 1-20 every time you want to do a knowledge check in case the information somehow decided to make itself easier to learn.

The truth is that there's no reason to ever have an opposed check where both parties roll dice. An opposed check is 2 skills compared to one another with a random variable inserted. It is just as effective (and much more efficient) if one of the parties does a take 10 on their check and the other person rolls a d20. It's still 2 skills. It's still a random variable introduced. And the odds are almost exactly the same in the middle range of the checks, where most of the opposed checks happen anyway. Unless your opposed check needs a range of 2-40, a d20 roll will suffice for all of your opposed checks.

D&D isn't the only guilty party. Dragon Age uses opposed checks every time the rogue tries to backstab. That means every round, the rogue is rolling a stealth roll, the DM is rolling a seeing roll and the player is rolling an attack roll. By making one of the stealth or seeing rolls a take 10, we've just eliminated 1/3 of the rolls in the sequence for no loss in effectiveness.

Whenever you are faced with an opposed roll, eliminate one of the rolls and do a take 10 for one of the participants. Generally, players like to roll their dice, so we can let them do the roll. In addition to giving them a little satisfaction, it also follows a nice pattern of the DM setting the difficulty for a task and the player trying to overcome it.

Also, it's important to make sure that only one person is doing a take 10 check. Otherwise, there is no randomness in the check and someone with a mere +1 bonus compared to their opponent will always be successful.

Odds of winning an opposed roll with a given bonus, using a d20 (red) or 2d20 (blue)

Increasing Your Odds
The only time the player rolling for a check rule runs into trouble is if the monsters have the opportunity to receive more than one roll. Perhaps five goblins are searching for the rogue hiding in the shadows. D&D already has a mechanic to simulate this: aid another. This adds +2 on to a roll for each helper. While it might not be 100% mathematically accurate, it's good enough to run a game with.

For this case, each helper adds +2 to the take 10 roll of the highest searcher, to a maximum of +6 for three helpers. This is a linear approximation of how rerolls affect the maximum result received on a d20:

Number of Rerolls vs. Maximum Result

You can make other rules to push the trend farther - such as adding +1 for every doubling of helpers after that, but the point of this was simplicity - so I'm sticking to a simple maximum of +6. If there is a significant number more opponents, I can give an extra +1-3 at my discretion.

This only applies if having more monsters would help the check, such as perception. If all the monsters are trying to hide, that becomes significantly more difficult as they now all need to make a successful stealth check. In this case, instead of getting a bonus to their roll, they take an equivalent penalty instead. So 2 cloakers trying to hide in shadows are at a -2 to hide together, while 4 of them would be at -6.

There are a few points to consider when using this rule. One is active checks versus passive checks, notably for perception and insight. A passive check is an automatic take 10 roll for all people involved. There is no bonus for being in a large group when all participants are using passive skills since there is normally no roll involved. When using active skills however, the above rules apply for having large numbers in the group. The above bonuses are only applied when normally the monsters would actually roll the dice.

A single monster who is actively using a passive skill like perception or insight receives a +2 on their skill check, so they add 12 to their active skill. This represents the fact that they have already failed their take 10 roll (the passive check) so they are using an active check to essentially reroll their check. In this case, extra searchers still help and count as extra rerolls, but the maximum bonus is still +6. (including the single monster's +2 bonus)

Initiative- a Hidden Opposed Check
An opposed check is defined as comparing the skills of 2 participants and each of them rolling a die to add on to their skill. In addition to perception vs. stealth and bluff vs. insight, it also describes initiative rolls. And once again, it is completely unnecessary. There are 2 rolls being used to determine one result.

Instead of rolling initiative for your monsters, have them do a take 10. Then all you need to do is arrange your players around your monsters' initiative scores as they call them out. You save yourself a few extra rolls and the results come out the same. That's time you can use to set up the encounter or add more minions to the battle map.

The next time you're ever rolling off against another player, save yourself some time. Take 10 and put the pressure on the player's die instead of your own.


  1. Interesting subject. We JUST decided to make our Initiative checks static - no rolls.

  2. I know I am in good company when I can put up charts and math and talk about gaming and someone calls it interesting. My wife wouldn't use those words. :)

    Using static initiative checks is definitely an option. It makes Improved Initiative and other initiative boosting options much more powerful. It depends how much you feel acting first in combat has an effect- most people think it's very important. But if your game can handle it, then it will help make your combats even faster.

  3. If you play that a tie goes to the initiator and the initiator is doing the roll then the red line in your first graph needs to be pushed up 0.05.

    If both checks have a 0 modifier then the player wins if they roll a 10+ which has a 55% chance. This means players have a slight advantage if the monsters always take 10. I'm not against that but just wanted to note it.