Utsuyamajō was constructed in 1524 by Nagaike Chikayoshi, a vassal of Imagawa Ujichika. Successive castellans included Ohara Chikataka and Asahina Yasunaga. The castle protected the surrounding bays on Lake Hamana. At this time the footprint of the castle may have only have covered the eastern end of the promontory.
It is thought that Utsuyamajō was expanded around 1562 in anticipation of the invasion of Tôtōmi by Tokugawa Ieyasu. The western castle appears to have been built specifically with the use of matchlock and artillery in mind for defence with stone-lined parapets. Asahina Yasumitsu was the castellan at that time.
In 1567, lord Asahina Yasumitsu was assassinated at the castle during a nō recital by his brother, Asahina Matsugu, who had become a secret ally of Tokugawa Ieyasu. In response to this, Obara Shigezane marched out of Yoshidajō under the orders of Imagawa Ujimasa and attacked Utsuyamajō, capturing it and killing the usurper. Obara Shigezane then took command of Utsuyamajō, comlpeting upgrades to the fort.
Sakai Tadatsugu, a general of the Tokugawa, was able to capture the fortress in 1568. Warriors Sawara Shigeyoshi, Naitō Sanzaemon, and Matsuno San'wemon helped conquer the fort. During this battle, Masuda Dan'wemon, the chief retainer of castellan Obara Shigezane, attempted to break out of the siege but was killed, leading to the fall of the castle. However, before the noose finally tightened around Lord Obara and the rest of his men, they detonated munitions in the castle as the enemy approached. The sound of the explosion caused the attackers to take cover, and, though no one was injued, when the smoke cleared it had become apparent that Obara had escaped.
When Tokugawa forces took over Utsuyamajō, Matsudaira Ietada was put in charge. In 1572, he was followed by Matsudaira Kiyoyoshi who was granted a small fief in the area worth 1,000 kanbun. Kiyoyoshi died in 1587, aged 82, but it is not known when the castle was abandoned.
Utsuyamajō is a yamajiro (mountaintop castle) ruin in the Iride Township of Kosai Municipality. The castle-mount sits on a peninsula overlooking Lake Hamana. Ruins feature kuruwa (baileys), horikiri (trenches), dorui (earthen ramparts), and ishigaki (stone-piled ramparts). The layout of the fortifications is intriguing and it is clear that Utsuyamajō was a large fortress. Generally the site can be split in two; between the lower, eastern castle-mount, and the upper, western castle-mount. It is presumed that the western castle was built after the eastern half due to the differences in construction.
The eastern portion of the castle is made up of a series of baileys separated by dry moats and embankments. I first tried to enter into one of the baileys above the road to the western castle, but it was too choked with bamboo to make progress. Next I tried to take a dirt road up past a house, itself thought to be built on a former bailey, and I made it into an outer bailey which was surrounded by dorui. The bailey itself was full of abandoned greenhouses. The second bailey was seriously overgrown and the path was blocked with fallen trees. I could barely see the otherside of the bailey due to pest plants so, having already visited the western castle at this point, I stopped my explorations here. Clearly the site was formerly cultivated and is now abandoned and heavily overgrown.
The western castle is the more interesting of the two halves. The road up to the castle is maintained because the cemetery of the temple below, Shōtaiji (presumed site of the castle's kyokan (living area)), was built on the terraced sub-baileys which climb the hillside to the castle proper. Behind the necropolis is a large dorui segment. A map displayed on-site indicated a tatebori (climbing trench) somewhere beneath here, but I think it must be lower down on the slope.
The most intriguing feature of Utsuyamajō may be the ishigaki which supports the inside of the dorui which surrounds the main bailey of the western fortress. Usually we'd expect to find ishigaki on the outside of the bailey to create steep walls, but in Utsuyamajō's case the outside of the bailey's ramparts is earthen, whilst the inside has a 1.2m high wall of stacked stones like a retaining wall. It is believed that this wall was made by the castle-builders so that they could stand behind the parapet whilst firing guns and cannon, and that there was no dobei (parapet wall) with loopholes as we'd expect to see. The ishigaki actually replaces the dobei in this case!
I tried to follow the parapet all the way around the main bailey but most of the site is horrendously overgrown with a botanical tangle of various plants. I also descended down the far side of the main bailey where there are large terraces in a tripple band. Ishigaki can be found here too. I wasn't sure if these terraces and their retaining walls were originally part of the castle or built for agriculture.
There were so many spiders at this ruin that I was constantly assailed by threads of sticky web no matter where I turned. Even recollecting my exploration here makes me feel itchy. A woman who I thought might be visiting the cemetery actually came from the direction of the main bailey covered in sticky seeds, and she warned how hopelessly overgrown the bailey was. Even though this site gets visitors attracted by the ishigaki, and it is designated as a historical site by the municipality, it's in an awful condition, and I wish it could be better maintained.
|English Name||Utsuyama Castle|
|Founder||Nagaike Chikayoshi; Obara Shigezane|
|Year Founded||1524; 1567|
|Castle Condition||Ruins only|
|Designations||Local Historic Site|
|Historical Period||Pre Edo Period|
|Artifacts||Kuruwa, Dorui, Ishigaki, &c.|
|Features||trenches, stone walls|
|Access||Chibata Station on the Tenryū-Hamanko Railway; 40 minute walk|
|Visitor Information||24/7 free; mountain|
|Time Required||90 minutes|
|Location||Kosai, Shizuoka Prefecture|
|Coordinates||34° 45' 22.82" N, 137° 31' 58.98" E|
|Added to Jcastle||2023|
|Admin Year Visited||Viewer Contributed|
|Friends of JCastle|
|Nippon Shiro Meguri|