Sengoku period Immediately prior to the Sengoku period, the Takeda helped to suppress the Rebellion of Uesugi Zenshū (1416–1417). Uesugi Zenshū (d. 1417) was the kanrei chief advisor to Ashikaga Mochiuji, an enemy of the central Ashikaga shogunate and the Kantō kubō governor-general of the Kantō region. Mochiuji, lord of the Uesugi clan, made a reprisal against the Takeda clan in 1415. This reprisal began a rivalry between the Uesugi and Takeda clans which would last roughly 150 years until the destruction of the Takeda clan at the end of the Sengoku period. While this rivalry existed, the Takeda and the Uesugi still had a huge amount of respect for one another. Takeda Shingen Takeda Harunobu (1521 – 1573) succeeded his father Nobutora in 1540 and became shugo lord of Kai Province in present-day Yamanashi Prefecture. In this period the Takeda began to quickly expand from their base in Kai Province. In 1559, Harunobu changed his name to the better-known Takeda Shingen. He faced the Hōjō clan a number of times, and most of his expansion was to the north, where he fought his most famous battles against Uesugi Kenshin. This series of regional skirmishes is known as the Battles of Kawanakajima. The battles began in 1553, and the best known and severest among them was fought on September 10, 1561. Shingen is famous for his tactical genius, and innovations, though some historians have argued that his tactics were not particularly impressive nor revolutionary. Nevertheless, Shingen is perhaps most famous for his use of the cavalry charge at the Battle of Mikatagahara. The strength of Shingen's new tactic became so famous that the Takeda army came to be known as the Kiba Gundan (騎馬軍団), or 'mounted army'. Up until the mid-16th century and Shingen's rise to power, mounted samurai were primarily archers. There was already a trend at this time towards larger infantry-based armies, including a large number of foot archers. In order to defeat these missile troops, Shingen transformed his samurai from archers to lancers. Decline of the Takeda clan Shingen died on May 13, 1573, at age 53 from illness. His son Takeda Katsuyori (1546–1582) effectively succeeded Shingen though the nominal head of the family was his grandson Takeda Nobukatsu; Katsuyori continued Shingen's aggressive expansion plan south and westward and was initially successful, briefly achieving the largest extent of Takeda rule. However, he was defeated in the Battle