Review of Kono kuni no kioku / A Chronicle of Japan.

According to "Nihongi: Chronicles of Japan from the Earliest Times to A.d. 697" page 57, it is now held in the Kambe of Kibi.

A Chronicle of Medieval Japan.

Nihongi: Chronicles of Japan from the Earliest Times to A.D. 697.

The story is detailed in the Nihon Shoki ('Chronicles of Japan').

The individuals credited by Chronicles of Japan for building the fortress were all former subjects of the ancient Korean Baekje Kingdom.

Nihon Shoki (Chronicle of Japan; also called Nihongi) - 30 volumes covering the mythological period through 697.

Shoku Nihongi (Chronicle of Japan, Continued; also called Shokki) - 40 volumes covering 697 through 791.

Nihon Kōki (Later Chronicle of Japan) - 40 volumes covering 792 through 833.

Shoku Nihon Kōki (Later Chronicle of Japan, Continued) - 20 volumes covering 833 through 850.