Because of that, the administration built a large number of yamajiro (castle in a mountain) and facilities for communication from the northern part of Kyushu to the coast of the Seto Inland Sea, and set up a defense facility called mizuki (water fortress) in the front line Dazaifu (local government office in Kyushu region) so that it could reinforce their defenses.
そのため、北部九州から瀬戸内海沿岸にかけて多数の山城や連絡施設を築くとともに、最前線の大宰府には水城という防衛施設を設置して、防備を固めた。