Yasumasa served Tokugawa Ieyasu from childhood and rose to become one of his chief retainers. He served in a notable capacity at the Battle of Anegawa (along with Honda Tadakatsu providing an attack on the flank of the Asai forces dangerously pressing Oda Nobunaga) and was present at Nagashino, helping to defeat Naito Masatoyo.

During the Komaki Campaign (1584) Yasumasa wrote up a statement attacking Hideyoshi and calling on support for the cause of Oda Nobuo and later accompanied Ieyasu to Osaka to meet with Hideyoshi himself (1586). During this trip he was awarded with the honorific title Shikibu-taiyû. in 1590 he participated in the Odawara Campaign. Following Ieyasu's move to the Kanto Region that same year, Sakikabara was given the castle of Tatebayashi and made the head of a committee responsible with assigning fiefs. While Ieyasu was away on Kyushu during Hideyoshi's Korean Campaigns Sakakibara acted as one of Tokugawa Hidetada's councilors and later was involved in the campaign against Uesugi Kagekatsu (1600).

Yasumasa was succeded by his son Yasukatsu, who fought at Osaka Castle (1614, 1615). The Sakikabara remained one of the Tokugawa's most trusted retainer houses into the Edo Peiod.

Yasumasa was also known as Sakikabara Heishichi and by his other titles, Koheida and Daijuji

Compiled by F.W. Seal