Retired Emperor Go-Toba (1180-1239) occupies a singular position in the history of the Japanese sword, not as a professional smith but as a sovereign whose personal devotion to the art of sword-making is extensively documented in classical sources including the Masukagami and the Jokyuki chronicles. As recorded in the Meizukushi (Kanchiin manuscript), Go-Toba summoned the foremost master smiths from various provinces to the imperial residence and established monthly rotations for sword forging. He is traditionally said to have personally performed the quenching (-ire) on blades, which were then marked with the imperial chrysanthemum crest (-) engraved on the tang in (hairline engraving), in either sixteen-petal or twenty-four-petal form. These works are accordingly referred to as Kikuzaku ("Chrysanthemum works") or Gosaku ("Imperial works"). During the Jokyu Rebellion, the Emperor bestowed these blades upon favored warriors of the Hokumen and Seimen guards to inspire distinguished military service.
The technical character of Kiku-go- varies according to the partner smith with whom the Emperor collaborated. Most examples follow the manner, presenting tight and somewhat subdued . Both -style and Kyoto-style examples survive. A distinguishing feature is the presence of at the base of the blade, which produces a -like effect and a weakened that may at first glance suggest (retempered work), though such blades are not retempered. In examples that have undergone (great shortening), these characteristic base features are no longer observable, and attribution relies upon the archaic tone of the and the quality of workmanship.
The consistently recognizes Kiku-go- as works of superior craftsmanship, noting that Go-Toba possessed expertise in appraisal that surpassed even professional specialists. The imperial chrysanthemum crests found on certain tangs are judged in character, providing critical documentary evidence. It is noted that the term "Kiku-," sometimes confused with Go-Toba's works in general usage, properly refers to blades bearing the character "" below a chrysanthemum , of which no authentic examples from this period survive today.