At first (1870), three diamonds represented a ship’s propellers, from the shipping company Tsukumo Shokai.

The name “Mitsubishi” refers to the three-diamond emblem. “Mitsubishi” is a combination of the words mitsu and hishi. Mitsu means three. Hishi means water chestnut, and Japanese have used the word to denote a rhombus or diamond shape.

The logo is based on the merger of two age-old Japanese dynasties who used a coat of arms with three similar diamond patterns. At first (1870), three diamonds represented a ship’s propellers. Mitsubishi was started as a shipping firm.