A library built in Kikuchi city famous for rich water and river. This library has a space formed by a bookshelf that draws a flowing curve named "Book River". We created a variety of places by this bookshelf with motif of citizen's identity Kikuchi River. The bookshelf changes various heights, becomes a seat, becomes a counter, or encloses a space like a wall. Big holes in the bookshelf, it becomes a tunnel, a window, a space like a capsule. The space that was softly partitioned by the bookshelf that transmits light creates a place of different atmosphere and creates rich communication.