Mizuki Fortress Ruins
[表のキャプション]
This 1.2-kilometer-long, heavily fortified earthen embankment was the first and only fortress of its kind. It was built in the mid-seventh century to defend Kyushu against foreign armies coming from Hakata Bay. Half a century later, it had become the Asian continent’s gateway to Japan.
[裏の解説]
In 664, Japan’s rulers feared an invasion from the Asian continent, and Hakata Bay seemed the most likely place for foreign ships to land. Just south of the bay was a large plain surrounded by mountains. If it could be fortified, this extremely defensible base would halt the advance of an invading army, effectively pinning it in the bay area.
To this end, the imperial court ordered the construction of a monumental barrier—an enormous earthen wall—to close the gap between two mountains south of the bay and block entry into the plain. Constructed using techniques from the Korean Peninsula, the Mizuki Fortress wall was 10 meters high. On its north side, the fortress had a 60-meter-wide moat that exceeded the maximum range of bows at the time. There were two gates, one to the east and one to the west. The western gate was reinforced with stone walls, and although the eastern one has not been excavated, it is presumed to have been the same. The earthen embankment was constructed of layer upon layer of soil, clay, and sand tamped down to form a solid, durable mound.
At that time, the Mikasa River flowed north to Hakata Bay through the center of where the new fortress was being built. Some research indicates that river water may have been directed through channels lined with stones; water flowed over them and beneath the embankment to fill the moat. Water was also drawn from surrounding river valleys. This clever use of water as a form of defense gave the fortress its name: “Mizuki” means “water castle.”
After the fear of invasion faded, Mizuki Fortress became the city of Dazaifu’s northern wall. Beginning in the late seventh century, foreign dignitaries and merchants were received in Dazaifu before they traveled east to the imperial capital. They entered through the fortress’s west gate, making it the literal and symbolic gateway to Japan. On the opposite end, Japanese officials and other domestic visitors coming from Nara or Kyoto entered Dazaifu through the east gate. Mizuki Fortress acted as a gateway until the twelfth century, even after its defensive role had ended.
Today, large sections of the Mizuki Fortress embankment can still be seen in Dazaifu and Ōnojō. The ruins of the west gate are located a few minutes’ walk from Mizuki Yume Hiroba Park.
