Itagaki Surinosuke served as a bushō during the Sengoku period. He was a retainer of the Kai-Takeda clan and, later, the Shinshū-Sanada clan.
Surinosuke was born as the son of Itagaki Nobuyasu. Nobuyasu originated from the Ozo clan, a branch of the Kai-Genji and, upon orders of Takeda Shingen, Nobuyasu inherited the name of the Itagaki clan. Surinosuke’s mother was a daughter of Itagaki Nobukata.
Nobuyasu, as the lord of Tanaka Castle, kept cavalry horses and was called Lord Itagaki of Tanaka. At the Fuji-Omuro Sengen Shrine in Yamanashi Prefecture and the Ikushima-Tarushima Shrine in Nagano Prefecture, written pledges and documents with personal seals have been passed down for generations. On 5/21 of Tenshō 3 (1575), after Naitō Masahide, the chamberlain of Minowa Castle in Kōzuke Province was killed at the Battle of Nagashino, Nobuyasu resided in the castle. Surinosuke accompanied his father. Takeda Katsuyori entrusted the governance of Kōzuke to Sanada Masayuki (the chamberlain of Shiroi Castle) and Nobuyasu as the chamberlain of Minowa Castle.
After the decimation of the Takeda clan by the Oda army in the third month of 1582, Surinosuke served Masayuki. In 1585, at the First Battle of Ueda in Shinano Province, Surinosuke fought valiantly. In 1600, at the Battle of Sekigahara, Masayuki joined the Western Army so, after the war, Masayuki was removed from his position while Surinosuke was released from service. Surinosuke did not serve a lord again but, in 1605, his son, Itagaki Hanemon, served Horio Tadaharu, a daimyō and the second lord of the Matsue domain in Izumo Province. In 1635, Surinosuke’s grandson from a daughter married into another family, Morohoshi Nobushige, served as a yoriki, or security officer, in an elite cavalry unit of the Edo bakufu known as the goshoinban. In the era of Hanemon’s son, Heiemon, Hanemon was released from service of the Horio family but, Heiemon’s son, Itagaki Tomosada, served Maeda Toshitsune and, thereafter, his descendants served as retainers of the Kaga domain for generations.