Mitsubishi's automotive origins date back to 1917, when the Mitsubishi Shipbuilding Co., Ltd. introduced the Model A, Japan's first series-production automobile. An entirely hand-built seven-seater sedan based on the Fiat Tipå 3, it proved expensive compared to its American and European mass-produced rivals, and was discontinued in 1921 after only 22 had been built.In 1934, Mitsubishi Shipbuilding was merged with the Mitsubishi Aircraft Co., a company established in 1920 to manufacture aircraft engines and other parts. The unified company was known as Mitsubishi Heavy Industries (MHI), and was the largest private company in Japan.