Iwatsuki Domain

 was a feudal domain under the Tokugawa shogunate of Edo period Japan, in Musashi Province (modern-day Saitama Prefecture), Japan. It was centered on Iwatsuki Castle in what is now part of Iwatsuki-ku, Saitama.
History.
Iwatsuki was an important strongpoint of the Odawara Hojo clan. However, following the destruction of that clan at the Battle of Odawara of 1590, the territory came under the control of Tokugawa Ieyasu, who assigned a 20,000 "koku" domain to one of his most trusted retainers, Kōriki Kiyonaga. Following the Siege of Osaka, his grandson Kōriki Tadafusa was awarded with a promotion to the 35,000 koku Hamamatsu Domain in 1619.
The following year, in 1620, the "rōjū" Aoyama Tadatoshi was awarded Iwatsuki with holdings of 55,000 koku. He subsequently fell from favor and was demoted to the 20,000 "koku" Ōtaki Domain in 1623.
Abe Masatsugu was transferred to Iwatsuki in 1638 from Odawara Domain. The Abe clan ruled Iwatsuki over the next five generations until 1681, gradually increasing their holdings to 95,000 "koku". After their transfer to Miyazu Domain, they were replaced by Itakura Shigetane (1681-1682), Toda Tadamasa (1682-1686), Matsudaira Tadachika (1696-1697) Ogasawara Nagashige (1697-1710) and his son Ogasawara Nagahiro (1710-1711).
The Nagai clan was then awarded Iwatsuki, beginning with Nagai Naohiro in 1711 and lasting for three generations until the clan was transferred to Kanō Domain in 1756.
Ōoka Tadamitsu (1709–1760), a distant relative of Ōoka Tadasuke who had started as a 300 "koku" "hatamoto", rose rapidly through the ranks and was eventually awarded Iwatsuki and 20,000 "koku" in 1756. His descendants remained at Iwatsuki until the Meiji Restoration. The final daimyō of Iwatsuki, Ōoka Tadatsura (1847–1920) sided with the pro-imperial forces in the Boshin War and made a viscount ("shishaku") in the "kazoku" peerage system in the Meiji period.
The domain had a population of 38,404 people in 6,962 households per a census in 1870.
Holdings at the end of the Edo period.
As with most domains in the han system, Iwatsuki Domain consisted of several discontinuous territories calculated to provide the assigned "kokudaka", based on periodic cadastral surveys and projected agricultural yields.