Mitsubishi's automotive origins date back to 1917, when the Mitsubishi Shipbuilding Co., Ltd. introduced the Mitsubishi Model A, Japan's first series-production automobile.[7] An entirely hand-built seven-seater sedan based on the Fiat Tipo 3, it proved expensive compared to its American and European mass-produced rivals, and was discontinued in 1921 after only 22 had been built.[8]
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.[9] MHI concentrated on manufacturing aircraft, ships, railroad cars and machinery, but in 1937 developed the PX33, a prototype sedan for military use. It was the first Japanese-built passenger car with full-time four-wheel drive, a technology the company would return to almost fifty years later in its quest for motorsport and sales success.[10]