Fantasy play and storytelling serve an important role in young children's development. While computers are increasingly present in the world of young children, there is a lack of computational systems that support children's voice in everyday storytelling, particularly in the context of fantasy play. This paper introduces StoryMat, a system that supports children's own voice in their own storytelling play. StoryMat offers a child-driven play space by recording and recalling children's narrating voices, and the movements they make with their toys on the mat. Empirical research with children showed that StoryMat fostered developmentally advanced forms of storytelling and provided a space where children engaged in fantasy storytelling collaboratively with or without a playmate. The paper addresses the importance of supporting children's fantasy play and suggests a new way for technology to play an integral part in that activity.

Keywords: Storytelling, young children, interactive narrative, interface, tangible interface