In the past, the weight of a one-mon coin (3.75 g) was a standard of weight. Its name, “momme”, derives from the Japanese words for “weight of one-mon coin”, and “匁” is the character used to depict this unit. Even to this day, the 5-yen coin weighs 3.75 g, which is equal to 1 momme. It is currently used as a weight unit for global pearl trading.