Construction began in 1601 (Keichō year 6). Yoshitaka, an expert at establishing fortifications, and Noguchi Kazunari, a stonemason who had worked on Edo Castle and Osaka Castle, 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 (making it the 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").