酒井氏
In 1634, Sakai Tadakatsu from a cadet branch of the Sakai clan at the Kawagoe Domain in Musashi Province became "daimyō" of the Obama Domain. Tadakatsu was one of the shogunate's top officials who served on the "rōjū" council, and later as its head, or "Tairō". The "kokudaka" of the domain under his tenure reached 123,500 "koku". Tadakatsu did much to establish the domain's governance and to ensure its strength and stability. He implemented a taxation system and installed town magistrates ("machi-bugyō") and local governors. The Sakai clan continued to rule Obama for fourteen generations over 237 years to the end of the Edo period.