Early Middle Japanese (中古日本語, Chūko-Nihongo) is a stage of the Japanese language between 794 and 1185, which is known as the Heian period (平安時代). The successor to Old Japanese (上代日本語), it is also known as Late Old Japanese. However, the term "Early Middle Japanese" is preferred, as it is closer to Late Middle Japanese (中世日本語, after 1185) than to Old Japanese (before 794). Source: Wikipedia (en)