About Shaku Measurements
In traditional Japanese craft, measurements are determined using the shaku, 尺, span, which originated in the span of the human hand between the thumb and forefinger. In former times, the length of the shaku varied until two lengths were established, the kane-jaku and the kujira-jaku. The kane–jaku, 曲尺, bend-span, which is equivalent to a standard foot of twelve inches, and the kujira-jaku, 鯨尺, whale-span, which is the equivalent to 14 7/8 inches. Certain artists and craftsmen use either shaku in their work. To avoid possible confusion, in modern times measurements are usually given in centimeters.
A shaku is divided into ten sun, 寸, which is divided into ten bu, 分, which is divided into ten rin, 厘.