Young children often build various structures with wooden blocks; structures that are often used for pretend play, subtly improving children?s creativity and imagination. Based on a traditional Japanese wooden block toy, Tsumiki, we propose a novel interactive toy for children, maintaining the physical assets of wooden blocks and enhancing them with automation. We name our interactive toy "TSU.MI.KI." "TSU.MI.KI" consists of a set of computerized blocks equipped with several input/output devices. Children can tangibly interact with a virtual scenario by manipulating and constructing structures from the physical blocks, and by using input and output devices that are integrated into the blocks. TSU.MI.KI retains the physical advantages of its ancient predecessor and adds a distinct interactive layer that supports creativity by imitating a storyteller or a supportive caregiver.