Which game is this six-sided die with two sets of runic-looking plus, minus and empty sides from?
These are fudge or fate dice used for the fudge role playing game.

Fudge uses customized &quot;Fudge dice&quot; which have an equal number of plus, minus and blank sides. A number of these dice are rolled, usually four at a time (&quot;4dF&quot; in Fudge dice notation), and for every plus side that comes up the result of using the Trait is considered one step higher (e.g. from Fair to Good) and for every minus side that comes up the result is considered one step lower. The goal is to match or surpass the difficulty level, also on the adjective scale, of the test. Thus, a Good attribute is considered to be Great if the player were to roll two plus sides, one minus side, and one blank—the minus side cancels out one of the plus sides and the remaining plus side raises the result by one step. The same Good attribute would be considered Poor if you were to roll three minus sides and one blank. The same dice roll can be achieved with six-sided dice, treating a 1 or 2 as [−], a 3-4 as [ ] and a 5-6 as [+].


Note: the symbols in the corners are +, - and 0.