Ōtsuchi Explained

An is a large wooden war mallet used by the samurai class of feudal Japan. The ōtsuchi had a shaft of about 6 ft (182.88 cm) much like the ono (war axe).^[1] It was mainly used for door breaching.^{[2] [3]}

Notes and References

1. https://books.google.com/books?id=IQ3FAZG94ZsC&q=war+mallet&pg=PA119 Samurai: The Weapons and Spirit of the Japanese Warrior, Author Clive Sinclaire, Publisher Globe Pequot, 2004
2. https://books.google.com/books?id=wo3QAAAAMAAJ&dq=Japanese+war+mallet&pg=PA563 Frank Leslie's popular monthly, Volume 8, Editor Frank Leslie, Publisher Frank Leslie Pub. House, 1879, Original from Indiana University, Digitized Feb 3, 2009 P.563
3. https://books.google.com/books?id=XJDT2baaAZIC&dq=Japanese+war+mallet&pg=PA131 Pauley's Guide - A Dictionary of Japanese Martial Arts and Culture