Japanese Tangram (Chie no ita)
Written by Gan Ryōken 1742 (Kanpō 2) Kaga Bunko Collection 6580

Japanese tangram is a board in square shape, which is cut into seven pieces. They are to be placed in different positions so that many different shapes can be made as a puzzle.
he main part of this book offers problems containing 42 kinds of shapes, such as an octagon-shaped mirror and a flower vase). The latter half of this book contains the solutions to these problems.