The Storyteller system is a RPG system published by White Wolf Game Studio as the core system for their original old World Of Darkness (oWoD) setting. It was published as part of the core rules for each of the RPGs in the WoD.
The Storyteller system uses d10 dice in a Dice Pool mechanism, where you count the number of dice in the pool that roll equal to or greater than a Target Number as successes. In the earlier games, this Target Number was variable, in later games it was fixed at 7. A variable number of successes may be needed to be successful overall.