Lifespan: 15xx to 4/29 of Keichō (1615)
Other Names: Masashige, Saburōzaemon
Lord: Takeda Shingen → Ban Naoyuki
Father: Yamagata Masakage
Siblings: Masamitsu, Masahisa, Masashige, Nobutsugu, Genpachirō, sister (formal wife of Saigusa Masasada), sister (wife of Aiki Jōrin), sister (formal wife of Yokoi Tadamatsu)
Adopted Siblings: Sadamasa, Tarōemon
Yamagata Masashige served as a bushō during the Azuchi-Momoyama and early Edo periods.
Masashige was born as the second son of Yamagata Masakage, the infamous senior retainer of Takeda Shingen. According to one theory, he was the fifth son.
Through ill fate, he served as a chief retainer to Ban Danemon Naoyuki. For the Siege of Ōsaka, he followed Naoyuki by returning from the road to Ōmi to enter Ōsaka Castle.
On 12/17 of Keichō 19 (1614), Masashige participated in the Nighttime Attack on Honmachibashi. Following after Ninomiya Naganori who had a head start, Masashige was the second to cross the bridge and the first to take an enemy head. Masashige was among twenty-three soldiers deployed for the nighttime attack, and, that same morning, he was called by Ōno Harunaga and Kimura Shigenari to the Senjō residence where Toyotomi Hideyori presented him with gold nuggets extracted from the river using a bamboo sluice.
On 4/29 of Keichō 20 (1615), a contingent of several tens of thousands of troops led by Ōno Harufusa with which Ban Danemon was affiliated departed from Ōsaka for the purpose of subduing Asano Nagaakira who was aligned with the Tokugawa. At this time, Masashige led a unit of thirty soldiers to engage vanguard forces fro Nagaakira in the Battle of Kashii.
Ban Danemon, Okabe Noritsuna, and Tannowa Shigemasa charged the vanguard troops of Asano Nagaakira, and clashed without being able to maintain communications with the main division under Harufusa. Masashige followed those in his unit and fought valiantly, engaging in spear fights against Ueda Shigeyasu and his retainers including Yokozeki Shinsaburō and Yokoi Heizaemon. Although he had Shigeyasu cornered, Heizaemon came to save his lord and cut-down Masashige while Shinsaburō took his head.
On 4/30, Masashige’s head was sent to Nijō Castle by Seki Ichibei and Terakawa Shozaemon. From Kadaura in Kii Province, twelve heads including, among others, those of Ban Danemon, Ashida Sakuuchi, Yokoi Haruzaemon, Yamauchi Gonzaburō, Sudō Tadaemon, Kumagai Chūdayū, Tokunaga Asaemon, Sakata Shōzaburō, and Yamagata Saburōemon were sent by boat along with a report on the war situation.