An adze. Also written 手斧. A carpenters' tool with a curved handle fitted with a blade. It is used for rough finishing of timber, or to achieve a distinctive dimpled finish called nagurimen 名栗面.
The expression *chōnahajime 釿始 refers to the special ceremony involving the chōna, carried out in the New Year to mark the start of the carpenters' work. It is difficult to trace the history of the chōna, but blade marks remaining on certain timbers confirm that it was already used for wooden temple architecture in the Asuka period. The handle is made from a branch. The blade is double-edged and about 10 cm wide. The upper surface of the blade has a large cutting angle while the under surfaces have an angle of only 2 degrees. Generally, the use of the chōna involves the carpenter supporting the wood with his feet and pulling the blade down vigorously toward himself, whittling away the surface wood little by little. It is a dangerous job and requires great skill.
