Roof tiles are considered to be the most universal relics among archeological data unearthed at ancient ruins, and they also offer much historical event information. For Ujidera, the clan's temple, tiles were introduced and used for its cloistered units from early on in the region. However, for the facilities directly maintained by the provincial government office, it is considered that the timing of the introduction and development of the tiles varied widely based on the state of its government even in the Nara period.
I have been discussing the state of the ancient Aki-koku up to this point; however, for comparison we analyzed eaves tile end piece designs and fabrication techniques of the eaves tiles unearthed from relics identified as being from the ancient Nagato-koku provincial office, posting stations, and Kokubunji provincial temple, which all belong to the same San'yo-dō.
As a result, different type of eaves tile end piece designs have been found over different periods of time; however, similar fabrication techniques are consistently used from the beginning. In addition, eaves tile end pieces were introduced to the provincial office earlier and then to the Kokubunji provincial temple. For this reason, it is presumed that in Nagatokoku, as it is for the Aki-koku, tile makers who belonged to the provincial government office workshops were producing tiles.
I also studied the eaves tiles unearthed in the Suou-koku, and it is estimated that tile makers were dispatched from the provincial government office workshops of Nagato to this province for a certain period of time as many similarities have been found in the eaves tile end piece design and its fabrication technique between these two regions.