This style of rolling was first used by Mayfair games and made popular by the DC Heroes RPG. I have taken this mechanic and applied it in a different way. So, let's go over how to roll! Roll 2 10-sided dice (2d10) and add up the results. So, if you roll a 4 and a 5, the result is a '9'. Now, for the fun part: if you roll the same thing on both dice, add the result and then you can roll the dice AGAIN and add that result to your total as well. So, if you roll a 4 and a 4, the result is an 8 AND you roll the dice again obtaining an 8 and a 3 for an end result of '19'. The fun part of this, is every time you roll doubles, you get to roll the dice again and add the result to your total. Unless you roll snake-eyes or a pair of 1s. Anytime snake-eyes is rolled, you automatically fail at whatever you were attempting, even if it is in the middle of a string of doubles.
There are a couple other reasons I favor this method of rolling. Although the excitement factor is a major reason I prefer exploding doubles, there are some mathematical reasons that I like this mechanic over the standard d20 method. Before I go further, I am just going to mention that I am not a mathematician, so I may not describe this well, in fact I doubt I can, however, there are two wonderful website that have really described the 'math stuffs' exquisitely well, and I have place their web addresses underneath the graphs they produced. Please visit their sites and read at least these entries, you will not be disappointed at all. In fact, you may find yourself spending a few hours reading other entries, I know I did!
First, using 2d10 creates a peaked curve, allowing more "average" results and less "extraordinary" results. For example: with a d20 you always have a 5% chance, be it to fail, or to perform unbelievably well. With 2d10 that chance is reduced to under 2% for the extremes and 10% for the common results, meaning you are more likely to perform a task with an average result. This graph does not show the effect of exploding doubles on results, but the exploding doubles serve to decrease the chances of a low extreme result (snake-eyes), while increasing the chances of obtaining a 20 or higher! This means less chance for failure, more chance for average result, and greater chance of above average result. This is of great benefit to the player!
On top of the previous reason, performing an extraordinary task is defined as "needing a 20" with a d20, and that could be something as ridiculous as moving the planet out of the path of the meteor by doing a push-up (Chuck Norris automatically succeeds). If left up to the dice, the character automatically succeeds on a 20, which means you have a 5% chance of doing something that exquisitely few people should be able to do, and even they probably have less than a 5% chance to do it! This leads to characters taking unbelievably ridiculous actions, since "if I need a '20' anyway, why not go for as much as I can?"! With exploding doubles, you maintain varying levels of difficulty over and above the '20' result, allowing the character to perform something ridiculously epic, you just have to roll exceedingly well, and be very lucky by rolling doubles and then doubles and then possibly rolling doubles again. This allows the wizard apprentice to slay a dragon with a spear in one epic, albeit lucky, shot and have it feel like an epic result, as opposed to "Well I win, I rolled a 20."
http://glimmsworkshop.com/2011/08/22/core-mechanics-randomization/
The next reason I selected this mechanic, is that it tilts the favor of combat to the more experienced, higher level opponent, as it should be. An opponent with more experience, more ability, or both should have an easier time bettering his adversary. Rolling 2d10 simulates this much more fluidly than 1d20 does, and the graphs show this fact. As you can see, when you roll a d20, you have a flat chance of success, and unless you use the rule that a '20' indicates automatic success, then anything above the 20 result is an impossible task. With 2d10 you can see the graph favors the lower difficulty tasks, while making the more difficult task tougher to accomplish. The graph does not show the exploding critical aspect of this rolling system, but if we were to add in the exploding doubles, it would increase the amount of successes for all difficulties. While this mechanic of 2d10 with exploding doubles eliminates the prospect of an impossible task (or removes the prospect of the blanket 5%), it makes that task more of a risk and allows the player to potentially aim for something that is more obtainable, such as a difficulty of 21 instead of a difficulty of 35.
I hope you enjoyed this insight into the primary rolling mechanic for the Viking Baby Games, and I look forward to blogging for you next week.
I definitely agree with the exploding doubles 2d10 system. When we were playing Mutants and Masterminds and we added this house rule in it made the roles much more exciting. The 2d10 aspect leveled the playing field a little bit and then the fact that you got that little thrill (even when you saw a pair of 2s) was very cool.
ReplyDeleteI particularly like the point about tilting the combat in favor of a more highly experienced character. Though I think it is important to note that the concept must be balanced against the fact that a mob of "level 1" commoners should have some chance of taking down a "level 10" hero. If attaining a higher level adds too much to a characters chance of success I feel like you lose some of the realism of the system.