The first castle on this site dates to the middle of the Muromachi period, when Shiba Kaneyori established himself as lord of the surrounding area of Dewa Province and built a fortified residence on the site of what is now the central bailey of Yamagata Castle. He later changed his name to Mogami Kaneyori, and the Mogami clan continued to rule for about 275 years. Mogami Yoshiaki rebuilt the castle in 1592, adding a second bailey and third bailey, and a number of two-story and three-story watchtowers. The castle never had a donjon. After the time of the Battle of Sekigahara, the Mogami ruled over a 570,000 koku domain; however, the clan was dispossessed by the Tokugawa shogunate in 1622. Thereafter the castle and Yamagata Domain passed through a large number of daimyo clans, often for less than a single generation, and its revenues were severely reduced. By the middle of the Edo period, the main bailey was allowed to fall into ruins, the second bailey was used as the residence of the daimyo, and the western half of the third bailey was plowed up for farmland. The castle was in the hands of the Mizuno clan at the time of the Meiji restoration. With the abolition of the han system in 1871, Yamagata Domain became Yamagata Prefecture, and in 1872 the castle grounds were sold to the government, and were used as a base for the Imperial Japanese Army’s IJA 32nd Infantry Regiment. Many sakura were planted around the castle grounds in 1906 to commemorate the Russo-Japanese War. After World War II the site of the castle became Kajo Park, containing the Yamagata Prefectural Museum. The East Gate of the castle and the site of castle keep were restored in 1986, and the Higashi Otemon Date of the second bailey was restored in 1991. In 2004 the stonework of the Inchimon Gate was restored, and a bridge leading to main bailey was reconstructed in 2006. Renovations and archaeological investigations are ongoing, and Yamagata City plans to restore as much of the castle as possible to its early Edo-period condition by the year 2033. The castle was listed as one of the 100 Fine Castles of Japan by the Japanese Castle Foundation in 2006.
