Sakakibara Yasumasa

Sakakibara Yasumasa
Lord of Tatebayashi
In office 1590–1606
Preceded by	none
Succeeded by	Sakakibara Yasukatsu
Personal details
Born	1548 Mikawa Province, Japan
Died	June 19, 1606 Edo, Japan
Nationality	Japanese

Sakakibara Yasumasa (榊原 康政^?, 1548 – June 19, 1606) was a Japanese daimyō 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-Shō (式部大輔).

Sakakibara Yasumasa was born in the year Tenmon-17 (1548), the second son of Sakakibara Nagamasa, in the Ueno district of Mikawa Province. The Sakakibara were hereditary retainers of the Matsudaira (later Tokugawa) clan, 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 non-existent treason plot against Oda Nobunaga.

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.

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