Minakuchi Castle (水口城 Minakuchi-jō), located in Kōka, Shiga Prefecture, is a hirayama-style (lit. "hill-top on a plain") castle also known as Hekisui-jō (碧水城, "deep blue water castle"), a reference to its reflection on the surface of the moat. It was constructed between 1632-1634 under Tokugawa Iemitsu. For most of the Edo Period, a branch of the Katō family (tozama-daimyō) ruled over the castle.

  • from 1682: a branch of the Katō family with a stipend of 20,000 koku
  • 1695-1712: a branch of the Torii family (20,000 koku)
  • from 1712 to the Meiji Restoration : the Katō (25,000 koku)


From the Muromachi Period on, and in particular in the Edo Period, Minakuchi played an essential role as a post town and the fiftieth stop on the Tōkaidō Road connecting the shōgun's capital Edo (present-day Tōkyō) with the imperial capital Kyōto. There were two castles by the name of Minakuchi in the region. The first one, called Minakuchi-Okayama, was constructed by Nagatsuka Masaie (長束正家, 1562–1600) who committed seppuku after being defeated in the Battle of Sekigahara in the year 1600. The construction of the second castle, partly modelled on Nijō Castle in Kyōto, began in 1632. It was conceived as a way station for Tokugawa Iemitsu at which he could stay during his travels between Kyōto and Edo, but it was used by the shōgun only once in fact.

The former castle was demolished and the building material used to construct the new fort on a nearby hill. Minakuchi Castle had no resident lord but was administrated by Tsubouchi Gemba (坪内玄蕃), a member of the bakufu. Although completed in 1634, it was not before 1682 that a new lord, Katō Akitomo (加藤明友, 1621–1684), moved into the castle. Akitomo was the grandson of Katō Yoshiaki (加藤 嘉明, 1563-1631), a retainer of Toyotomi Hideyoshi and lord of the Aizu domain who came to fame as one of the shichi-hon-yari (七本槍), or Seven Spears of Shizugatake, Hideyoshi's seven most trusted and experienced generals.

In 1695, the Katō family had to hand the castle over to the Torii, but in 1712 they were reinstated with a slightly higher stipend of 25,000 koku. The Katō never used the palace in the honmaru (本丸, the innermost bailey), but established their living quarters in the ninomaru (二の丸, second bailey). They resided at Minakuchi Castle until the Meiji Restoration, when parts of the castle grounds were sold and the edifices dismantled.


While most of the castle lies in ruins, parts of the inner castle were reconstructed in 1991, including segments of the wall, two gates as well as a yagura (櫓, corner turret). The honmaru features a fortified gate (東出, higashi-de) leading to the outer bailey. The castle was protected by stone walls and is encircled by a moat. The surrounding park was designed by Kobori Gonjūrō (小堀權十郎), a son of the famous landscape gardener Kobori Enshū (小堀 遠州, 1579-1647). The yagura houses a small museum on local history and customs (水口歴史民俗資料館, Minakuchi rekishi minzoku shiryōkan), and the castle grounds accommodate a parking lot and a baseball court of a local high school.

Access and admission:

Opening hours: 10:00 - 16:00
Admission: adults 100 JPY, children: 50 JPY
Access: less than 5-minute walk from Minakuchi Jonan Station (on the Ohmi Railway one stop from the JR Kibukawa Station)
Address: 〒528-0023 滋賀県甲賀市水口町本丸4−80
Phone: +81 748-63-5577