Within the corpus gathered here, every blade belongs to a single institution: the , the rotation of swordsmiths that the Retired Emperor Go-Toba (後鳥羽上皇) is recorded as having summoned to his cloistered palace (in no gosho) in the early period. The describe a consistent arrangement in which the sovereign selected appointed smiths (), organized them into alternating monthly shifts, and had swords forged on the imperial premises. Blades for which the Emperor himself performed the quenching (-ire) are termed or Gosaku. The do not name the individual smiths of the rotation by personal name; instead they identify the traditions from which the partner-smiths were drawn, citing the Ko- group, the Bichu manner, and the Yamashiro range. One entry grounds the institution in classical treatises, naming the Meizukushi (Kanchiin manuscript), the Masukagami, the Jōkyūki, and the study Gotobain Ban Kajikō. Because the men who served as the sovereign's counterpart came from these separate provincial lineages, the corpus is a historical grouping rather than one line of transmission.
The blades therefore divide along the very fault line the warn of, and the descriptions record two distinct hands rather than one shared idiom. The first group works in a mode: the Kuroda (Tokuju 21, 53) show with high and , a well-forged carrying vivid , and a high-tempered, flamboyant with and , -dominant with and a tendency. The second group is built on : the Yamauchi (Tokuju 11) and the "" ( 35) open with near the , giving a -like impression, then continue in a shallow with and , abundant , , and , with a diagonal -like at the base. The held by the Imperial Household Agency sit between these, showing with intermixed and in the manner with a tight . run with across the group; and the effect recur often enough that the treat them as a general marker of the type, while cautioning that such blades may at first glance resemble retempered () work though they are not.
The chrysanthemum crest is the connecting thread the return to throughout. At the base of the tang, executed in hairline , a of sixteen or twenty-four petals is recorded on the blades and as a worn remnant within the togidame of the Kuroda and the Itsukushima Jūyō-Bijutsuhin piece. Two blades add a tally-like character "一" beneath the crest; the note no other known parallel and value them as documentary evidence, while one entry separately cautions that the later term "Kiku-" is often confused with these imperial works. Provenance carries weight across the corpus: the Kuroda was bestowed by Tokugawa Ieyasu on Kuroda Naotsuna in Keichō 19 and is recorded in the Tsuchiya ; the Yamauchi and "" blades carry ; the descends from the Kujō regent house to Emperor Meiji; and the Itsukushima blade passed from Ōuchi Yoshitaka through Mōri Motonari to the shrine. As a group the blades stand as the surviving record of an imperial forge, read not through one style but through the divergent provincial hands the chrysanthemum gathered under a single crest.