Middle wheel with water and mallet wheel round clock

The name 'tsuchiguruma (mallet wheel)' is based on 'Heian Monkan'. / Old waterwheels had two types: one with a flat end and one with a ladle. The ladle type was adopted in the design and was called 'shojiguruma (ladle wheel)'. Although the ladle shape of the ladle wheel was cylindrical, adding a rounded shape would turn it into a mallet in terms of design. In other words, 'tsuchiguruma (mallet wheel)' is a design that connects a mallet to a wheel (a type of crest design) and represents a waterwheel. (From 'Exploring Family Crests' by Keiichi Morimoto)