were provincial officials in Classical Japan. They were nobles sent from the central government in Kyoto to oversee a province, a system that was established as part of the Taika Reform in 645, and enacted by the Ritsuryō system. There were four classes of kokushi, from the highest to the lowest: Kami (守), Suke (介), Jō (掾), and Sakan (目). In the Middle Ages, an acting governor called mokudai, the daikan of the kokushi, took over the local government of the province, while the kokushi returned to the capital to take on a supervising role. History The oldest reference to the term kokushi appears on the Seventeen-article constitution from 604. As part of the Taika Reform in 645, a new system of provincial government was established, marking the beginning of the kokushi. Before this, the governors were called mikotomochi (宰 or 使者). This term was replaced with the kanji characters 国 (province) and 司 (governor), and thus became known as kokushi. The kokushi were divided into four classes (四等官, sitōkan), from the highest to the lowest: Kami (守), Suke (介), Jō (掾), and Sakan (目). Japan was divided into 66 provinces and two islands, and the number of kokushi officials and classes appointed to each province depended on which of the four provincial classes (dai, jō, chū, and ge) it belonged to. They held considerable power, as they were in charge of the administration, finance, law, and military of the province. In the beginning, the term of office was six years, but later reduced to four years, with the exception of some special provinces. During the tenure, the kokushi received income through tax collection, and later received financial privileges that central government officials did not receive. As the ritsuryō system began to decline, the position of kokushi was seen as one type of income source. In September 826, princes of the Imperial Family were appointed as kokushi in Kazusa Province, Hitachi Province and Kōzuke Province. These kami-class kokushi were called taishu, and as they did not leave the capital and work at their assigned province, provinces with no local governor were born. In contrast to this, kami who left the capital to occupy their local office became known as zuryō. After the 10th century, following the instability of the ritsuryō system, the former duties of district governors (gunji) and lower officials were taken over by the kokushi, making the kokushi