|Structure||3 levels, 3 stories|
|Admin's Rating||★ ☆ ☆ ☆ ☆|
|Historical Site||Prefectural Historic Site|
|Location||Gyoda, Saitama Prefecture|
|Access||Gyoda Station (Takasaki Line), bus or walk 25 minutes|
|Website||Gyoda City Board of Education - Gyoda City Museum|
|Visited||August 29, 2001|
|Notes||My book said to go to the castle by bus from Gyoda station but there are only a few busses per day and I would have had to wait nearly two hours for one, so we ended up walking the 4 kilometers to the castle. If you'd like to visit Oshi-jo, there are many more busses leaving from Fukiage Station. Although I did not visit them, there are also many kofun in the area that may be of interest to history enthusiasts.|
Oshi-jo was completed by Narita Akiyasu around 1479. The Narita family ruled over the area of Gyoda for about 100 years until the castle fell to forces loyal to Hideyoshi in his assault on the Kanto area. Oshi-jo was considered to be well designed in that it made use of the many marshes and swamplands in the surrounding area to its defense. These marshes proved to be valuable defenses in the initial attack by Ishida Mistunari.
Ishida Mistunari brought 23,000 troops to take control of Oshi-jo after having defeated Tatebayashi-jo just three days earlier. Compared to this legion of seasoned warriors, Oshi-jo had a complement of approximately 619 samurai and another 2,000 soldiers made up of local farmers and townspeople. With the help of the natural defenses provided by the area, these people amazingly held off Mitsunari's army and forced him to regroup and consider a different approach
Just as Mitsunari was defeated by the swamplands surrounding Oshi-jo and Gyoda, he devised a new plan to make use of nature himself. He put his samurai to work building walls and in 6 days they completed 28 kilometers of walls to divert the water of two local rivers into the town to flood the castle. This water assault began on July 6 and the heavy rains of the rainy season also aided in Mitsunari's efforts to flood the town. However, since the castle was built on a slightly higher elevation, it remained undamaged.
During this time, Narita Ujinaga, the master of Oshi-jo, had actually been fighting with the Hojo at Odawara while his younger brother Nagachika defended the castle. Once Odawara fell to Hideyoshi, Ujinaga sent word to Nagachika to surrender the castle. After the Tokugawa moved to Edo, Oshi-jo fell under the control of Ieyasu who placed his fourth son Tadayasu in charge.
This tenshu was actually reconstructed in the original Sannomaru.