Fukuoka Castle is a Japanese castle located in Chūō-ku, Fukuoka, Japan. The castle is also known as Maizuru Castle or Seki Castle. Completed in the early Edo period for tozama daimyo Kuroda Nagamasa, it has been decreed a historic site by the Japanese government.
In 1600, Nagamasa received huge rewards of land in Chikuzen Province for their contributions at the Battle of Sekigahara, and moved into Najima Castle to form the Fukuoka han. Najima Castle had been created by Tachibana Akitoshi and was expanded by Kobayakawa Takakage, but was much too small to accommodate a large han, leading to the selection of Fukusaki hill as the new castle site.
Construction began in 1601 (Keichō year 6). Yoshitaka was already an expert at establishing fortifications, and Noguchi Kazunari, a stonemason who had worked on Edo Castle and Osaka Castle, also directed the construction. Completed in 1607 (Keichō year 12) after seven years of work, the castle is said to have contained an impressive 47 yaguras, and covered an area of 47,000 square metres (largest in the Kyūshū region). Katō Kiyomasa of the nearby Kumamoto han lauded the castle for its grandeur. The dry stone fortification designed by Noguchi was especially impressive, giving the castle the name "Seki-jō" (literally "Stone Castle").
Defensive Elements Outside Castle
Defensive elements can also be seen in the areas outside the castle. To the east of the outer castle, Hakata had already been fortified when the castle construction began. The defensive lines of this mercantile city probably appeared during the time of the Mongolian Invasions in the late 13th century, when a series of walls to thwart the invaders were constructed. In the 16th century, amid the age of civil wars, Hakata was fortified in full-scale by diverting the course of the Hie (Mikasa) River to the east of Hakata, and excavating moats on the south. After the construction of Fukuoka Castle, Hakata seems to have been designated as a demaru (a detached work, placed in front of a gate to cover it) defending the Higashi-toriire Gate together with Nakajima (a man-made island on the estuary of the Naka River). On the east of Hakata, there was the Ishido Entranceway and Gate, and on the south, the Tsujinodo Entranceway and Gate. Although these gates were located outside the outer castle of Fukuoka Castle, they were still designated as castle gates.
The Yakui River, which was to the south of the outer castle, not only made up a defensive line itself, but also played an important role in preventing the moat around the inner castle, the Naka Moat and the Hizen Moat, from accumulating with the silt which flowed from the heights of the hills on the south of the inner castle. In Empo 6 (1678), a bridge that connected the Haruyoshi Town and the Kazuma Gate Entranceway was newly built. It was laid obliquely so that enemies could not attack the gate directly. To the west of the castle, there were the Komo (Myoan-ji) River and the Hii (Tajima) River, which served as defensive barriers.