Sakakibara Yasumasa

Sakakibara Yasumasa (榊原 康政) was a Japanese daimyo of the late Sengoku period through early Edo period, who served the Tokugawa clan. As one of the Tokugawa family's foremost military commanders, he was considered one of its "Four Guardian Kings" (shitennō 四天王). His court title was Shikibu-dayū (式部大輔).

Background
Sakakibara Yasumasa was born in Tenmon 17 (1548), the 2nd son of Sakakibara Nagamasa, in the Ueno district of Mikawa Province. The Sakakibara were hereditary retainers of the Matsudaira (later Tokugawa) clan, being classified as fudai. However, they did not serve the clan directly, but instead served one of its senior retainers, which at that time was Sakai Tadanao (which classified the Sakakibara as baishin, or "rear vassals"). The young Yasumasa interacted with Matsudaira Motoyasu (later Tokugawa Ieyasu) often from a young age, and was soon appointed his page. Due to his valor in the suppression of the Ikkō-ikki uprising in Mikawa, he was allowed to use the "yasu" from Ieyasu's name.

At this time, he unseated his brother and became head of the Sakakibara clan. There are two explanations for this. One is that his brother had been an ally of the Ikko Ikki rebels, and the other is that his brother was a retainer of Ieyasu's son Matsudaira Nobuyasu, who was implicated in what was most probably a fraudulent treason plot against Oda Nobunaga.

Adulthood and Service as One of the 'Four Guardians'
In Eiroku 9 (1566), at age 19, Yasumasa had his coming-of-age ritual, and soon after, he and Honda Tadakatsu were made hatamoto by Ieyasu, and each granted command of 50 cavalrymen. From that point on, they would function as Ieyasu's hatamoto unit commanders.

Yasumasa battled at Anegawa during the year of 1570, The Mikatagahara during the year of 1573, along with the Nagashino during the year of 1575. When the latter chose to defy Toyotomi Hideyoshi, Yasumasa still served under Ieyasu, suggesting the region of Komaki, suited for the currently ensuing campaign. Yasumasa was given the title of "Shikibu-dayū", when accompanying Ieyasu to Osaka to meet with Hideyoshi. After the Tokugawa moved to the region of Kantō, he was to have a team responsible for the allocation of fiefs. While Ieyasu was serving as one of Hideyoshi's staff in the region of Kyūshū, Yasumasa was to supervise Kantō, as one of the chief administrators.



Later life
Yasumasa received the 100,000 koku fief of Tatebayashi han following the Tokugawa victory at the Battle of Sekigahara, which remained in the family for a few generations. Yasumasa himself died in 1606, at the age of 59, and is buried at Zendoji Temple in Tatebayashi, where his grave still stands.