The recent kerfuffle over the Dungeons and Dragons OGL has me wondering whether I can turn my 2d10 conversion of D&D into its own stand-alone, non-OGL system. There's a lot I would need to do to make that work, but let's start with the advantage/disadvantage mechanic. I want to take a system where you can add d10s to 2d10 rolls, but universalize it and limit it. So to that end, let's introduce the idea of the Weal and Woe dice pools:
The universe is strangely balanced, whether by gods, some unknown purpose, or just random chance. Good luck always follows bad, and bad luck follows good. In the game, this is represented by the Weal and Woe dice pools. While dice are more tactile and intuitive to use for these pools, tokens, coins, tallies on a sheet of paper, or a tracker on a virtual table top may be used instead.
At the end of each rest, each pool starts with 5 d10s. After a player rolls 2d10, there are circumstances where he or other players may roll an additional die from the weal pool, or where the GM may roll an additional die from the woe pool. No player (including the GM) may roll more than one die from his pool for any 2d10 roll. After all dice are rolled, the players (including the GM), in the order that they rolled their dice, select one of the rolled dice (including the original 2d10 dice) and place that die in the opposite pool from the one they drew their die from. The remaining two dice are the final roll.
If any final 2d10 roll (after any Weal and Woe dice are added and the selected dice are sent to their pools) is a double, and that doubled number is greater than the amount in the Weal pool (if a player is rolling the 2d10) or the Woe pool (if the GM is rolling the 2d10), then move a die from the opposite pool to the 2d10 roller’s pool. So if there are five dice in each pool, and a player rolls two 6s, move a die from the Woe pool to the Weal pool. This has the effect of balancing the pools over time.
The circumstances where players may roll dice from the pools are the following:
- Before the player rolls his 2d10, the GM may declare that the circumstance is either favorable or unfavorable. With a favorable circumstance, the player may choose to roll a die from the Weal pool after his roll, and select a die to discard to the Woe pool. With an unfavorable circumstance, the GM may roll a die from the Woe pool after the roll, and select a die to discard to the Weal pool. Alternatively, if it's an enemy who suffers an unfavorable condition, the player may roll from the Weal pool to cause him misfortune, and an enemy with a favorable condition gains his extra die from the Woe pool.
- Players may select to aid another player. To do so, they must have training in the skill, or another ability relevant to what the other player is attempting. They also must forgo making an attempt themselves, and share in the consequences if the final roll is a failure. The duration over which the helper can’t make an independent attempt depends on the situation. You can help someone else make an attack by feinting, but you can’t make an attack in the same turn. You can help someone climb a wall, but you can’t make progress climbing the wall yourself at the same time. If you’re trying to help someone recall some lore, or figure out a mechanism, it’s assumed that you’ve already given it your best shot, and you can’t try again until they can, when the circumstances change—you gain access to a new tool or research materials, for example.
- Certain ancestral, class, or other features may allow you to draw from the Weal pool either to help in your own 2d10 roll or an ally’s. On the other hand, certain monster abilities allow them to draw from the Woe pool.
- The party or the GM declares that every roll for one side in the combat has one higher degree of success, and every roll for the other side has one lower degree of success, than the dice actually show, until the beginning of the turn of the character when that is declared (I'll discuss how degrees of success work for attacks later).
- The party or the GM declares that a single roll is a double 10, no matter the circumstances of the roll.
- A party or GM can describe a lucky break, introducing a circumstance or random chance brought on by the preponderance of luck on one side. The GM may start a random encounter with a deadly foe, a player may declare the arrival of a strong ally. The circumstances of the lucky break doesn’t last beyond a single encounter.