was a Japanese samurai lord of the Sengoku period. He was the son of Hà Âjà  Sà Âun, the founder of the Go-Hà Âjà  clan. He continued his father's quest to gain control of Kantà  (the region around present-day Tokyo).
In 1524, Ujitsuna took Edo Castle, which was controlled by Uesugi Tomooki, thus beginning a long-running rivalry between the Hà Âjà  and Uesugi families.
In 1526, Hojo Ujitsuna was defeated by Takeda Nobutora in the Battle of Nashinokidaira. Later, the Uesugi attacked and burned Tsurugaoka Hachimangà « in Kamakura, which was a major loss to the Hà Âjà  symbolically, because the earlier Hà Âjà  clan from which they took their name fell in the Siege of Kamakura (1333). (Ujitsuna soon started rebuilding Tsurugaoka Hachimangà « and was completed in 1540.) In 1530, his son Ujiyasu defeated Uesugi Tomooki in the Battle of Ozawahara.
The Uesugi attacked Edo again in 1535, when Ujitsuna was away fighting the Takeda; however, Ujitsuna returned and defeated Uesugi Tomooki reclaiming his lands.
When Uesugi Tomooki died in 1537, Ujitsuna took the opportunity to occupy Musashi province and seize Kawagoe Castle to secure his control of the Kantà Â.
In 1538, Ujitsuna then went on to win the battle of Kà Ânodai, securing Shimà Âsa Province for the Hà Âjà Â.
In 1539, he defeated the Koga Kubo Yoshiaki (Oyumi Kubo) and gained control of Awa Province (Chiba).
Over the next several years before his death in 1541, Ujitsuna oversaw the rebuilding of Kamakura, making it a symbol of the growing power of the Hà Âjà Â, along with Odawara and Edo. He was succeeded as head of the Hà Âjà  clan and lord of Odawara by his son Hà Âjà  Ujiyasu.