Sagara Castle

In 1767, Sagara was awarded to Tanuma Okitsugu, rōjū to Shōgun Tokugawa Yoshimune, Tokugawa Ieharu and Tokugawa Ieshige. He is known for the Tenmei economic reforms. At the time, the shogunate was in a dire economic situation with the development of a monetary economy outstripping the traditional rice-based stipend system for the samurai class, which caused ever increasing debt. The government applied fiscal restraint by reducing the budget, increasing tax and suppression of commerce, but this also bought deflation. Tanuma used the opposite approach, encouraged commerce and protected merchants through guilds in exchange of taxes. He also adopted positive fiscal policy such as increase of monetary base, and made large scale public works projects. These policy intended to increase tax revenue by developing of economy. Due to the initial successes of his reforms, and his close relations with the shogun, he was promoted from a relatively low status to daimyō and was allowed to construct an actual castle on the site of the Sagara jin'ya.

The castle took 12 years to complete, and was on a large scale with am inner bailey, second and third bailey, and an outer enclosure, all surrounded by moats and stone walls. The total dimensions of the castle were approximately 500 meter by 400 meters. Also of note was that Tanuma constructed a three-story donjon, which was very rare for the mid-Edo period. He also developed the town surrounding the castle as a jōkamachi and encouraged the development of commerce.

However, this period of prosperity did not last. Tanuma made many enemies in his rise from relative obscurity, and conservative strongly disapproved of his commerce-based reforms. His administration was accused of massive corruption. The Great Tenmei famine and a eruption of Mount Asama caused further disruption, and increasing inflation caused riots in Edo. With the death of Shogun Tokugawa Ieharu, Tanuma fell from favor and was demoted to Shimomura Domain in Mutsu Province. Sagara reverted to tenryō status, and Sagara Castle was destroyed after only 10 years of its completion.

In 1823, Tanuma Okitsugu's son was allowed to return to Sagara, but with a kokudaka of only 10,000 koku. He was allowed only a jin'ya, which he built on the ruins of the former castle, and from which the Tanuma clan ruled until the Meiji restoration. All that remains of the fortifications today are some partial stone walls. However, the daimyō palace survived and was relocated to a temple located in the neighboring city of Fujieda.

• Schmorleitz, Morton S. (1974). Castles in Japan. Tokyo: Charles E. Tuttle Co. pp. 144–145. ISBN 0-8048-1102-4.
• Motoo, Hinago (1986). Japanese Castles. Tokyo: Kodansha. p. 200 pages. ISBN 0-87011-766-1.
• Mitchelhill, Jennifer (2004). Castles of the Samurai: Power and Beauty. Tokyo: Kodansha. p. 112 pages. ISBN 4-7700-2954-3.
• Hall, John Whitney (1955). Tanuma Okitsugu (1719-1788): Forerunner of Modern Japan. Harvard University Press. p. 222 pages. ISBN 0674868218.

• Temple of Daisei-ji, where a surviving building of Sagara castle is located