Koei

Koei Co., Ltd. is a Japanese video game developer and publisher known for historical simulation and strategy games. It was founded in 1978 by Yoichi Erikawa and Keiko Erikawa in Japan. Early successes included Nobunaga's Ambition (1983) and Romance of the Three Kingdoms (1985), which helped establish Koei as a major producer of strategy and simulation titles. The company also developed the Dynasty Warriors series, a hack-and-slash franchise launched in 1997 that expanded Koei's reach into action gameplay while drawing on its historical settings.

In 2009 Koei merged with Tecmo to form Tecmo Koei Holdings, later renamed Koei Tecmo Holdings. The merger combined Koei's emphasis on historical strategy with Tecmo's action franchises, such as Dead or Alive and Ninja Gaiden, creating a broader global publisher and developer.

Under Koei Tecmo Holdings, the Koei label continues to be used for strategy and simulation titles, while the group publishes and develops a wide range of games across platforms, including console, PC, and mobile. Notable series associated with the company include Romance of the Three Kingdoms, Nobunaga's Ambition, and Dynasty Warriors, with new installments periodically released and older franchises receiving remasters or ports.