The company initially focused on personal computer sales and made-to-order business software. In 1982, the company released the erotic title (eroge) , which was an early role-playing adventure game with color graphics, owing to the eight-color palette of the PC-8001 computer. It became a hit, helping Koei become a major software company. In 1983 it released , a historical strategy game set during the Sengoku period of Japanese history. The game went on to receive numerous awards, and Koei produced several more such games set against the backdrop of world history, including "Romance of the Three Kingdoms", set during the Three Kingdoms period of Chinese history, and , set in Portugal during the Age of Exploration.