The old registers list several smiths for the Ayanokoji school of Kyoto, Sukesada, Sadaie, a second Sadatoshi written with different characters, Sueyuki and Tadaie among them, yet of them all only Sadatoshi[[c:1]] survives in signed work. The published sources count the Ayanokoji, with Awataguchi and Rai, as one of the three lineages of Yamashiro swordsmiths in the Kamakura period; the school takes its name from the smiths resident on Ayanokoji street in Kyoto's Shijo quarter, and "its founder is Sadatoshi"[[c:2]]. On his date the registers do not agree: the Noami Meizukushi places him around Hoji (1247-48), the Kokon Kaji Meizukushi around Bun'ei (1264-75), and one tradition relates that he was on friendly terms with Rai Kuniyuki, the two even producing substitute works for one another as demand required. Within the school the only other hand attested in surviving work is Sadayoshi; the remaining register names survive in no blade at all.
Surveying the extant works as a whole, the published sources return to a single formulation: his manner follows the working range of the old Kyoto makers of the Sanjo and Gojo schools, an archaic elegance that calls Awataguchi Kuniyasu to mind. His classic tachi is slender, the taper from base to tip marked, the koshizori high with funbari, closing in a ko-kissaki. The hamon is a ko-midare mixed with ko-choji and ko-gunome over a suguha tone, the intervals of the undulations close, the pattern small and intricately complex. Along the yakigashira, still smaller patches of yaki, with yubashiri and tobiyaki, appear in dotted succession and build an effect akin to nijuba. Above all the nioiguchi clouds softly: this urumi is what the published record names "one of his viewing points"[[c:3]], and the rare blade without it is noted as the exception. From precisely these traits the NBTHK draws its chronological conclusion, the workmanship being "appraised as going back earlier than the conventional view"[[c:4]].
The jigane is a well-knit ko-itame, in places mixed with nagare or a slightly standing itame, with fine ji-nie lying thick, fine chikei, and a nie-utsuri that stands out; jifu-like patches mix in on some blades. At its best the jigane carries a moist, viscous quality, and of one Tokubetsu Juyo tachi the published sources write that it precisely accords with the phrase of the old tradition texts, "appearing viscous and sticky"[[c:5]]. Within the ha, ashi and yo enter frequently, ko-nie adheres, and fine kinsuji and sunagashi run through. The boshi continues the temper quietly with hakikake, at times taking on a flame-like appearance or finishing yakizume, on some blades entering midare-komi with a small ko-maru return.
Two registers carry the attribution. The signed tachi bear a two-character mei, the character Sada cut large in a cursive manner and the character Toshi smaller[[c:6]], set low on the nakago toward the mune and at times avoiding the groove, a placement the published sources note on the tachi designated National Treasure as well. Most signed blades are suriage; an ubu nakago is recorded as rare among his works, and one katana preserves the signature folded back as an orikaeshi-mei rather than lose it to the shortening. The o-suriage mumei katana are appraised by the same marks: the published sources speak of work that conforms to "the rules of Sadatoshi"[[c:7]], and the best of the unsigned blades are said to show "a style directly connected to his signed works"[[c:8]]. No dated work survives, and the scholarship turns on that absence. The registers' Bun'ei dating sits against the archaic cast of everything extant, so the NBTHK re-reads the old substitute-work legend rather than discard it, concluding that if there was indeed a point of contact between Sadatoshi and Kuniyuki, "it would fall at Sadatoshi's late years and the beginning of Kuniyuki's"[[c:9]].
A minority of blades departs from his usual make. In these the nioiguchi is bright and clear without urumi, the temper led by choji on a suguha tone, and the published sources read them toward the younger Kyoto master: one Tokubetsu Juyo tachi is described as "a make recalling Rai Kuniyuki, the nioiguchi brightly clear"[[c:10]], the activity within its ha splendid. His place among the Yamashiro smiths rests on his own tells, the tightly packed small-pattern midare, the dotted nijuba effect along the yakigashira, and the softly clouded nioiguchi, the very features the published record treats as evidence for setting him a generation before his registered date. At the other end of his range stands the blade the sources judge the most archaic of all his works, a grand ubu signed tachi read as probably of his initial period, in which the connection to Awataguchi Kuniyasu can be plainly discerned. The school he founded continued only narrowly; with Sadayoshi the sole other attested hand, the surviving Ayanokoji work is concentrated almost entirely in Sadatoshi's own name.
Fujishiro grades him Jo-jo saku, and forty-three designated works stand on record. One is a National Treasure, the tachi in the care of the Tokyo National Museum, of which Honma records that among all the Sadatoshi he had examined it is the finest; three more are Important Cultural Properties, and five hold Juyo Bijutsuhin certification, among them blades once owned by Maeda Toshinari and by Kurokawa Fukusaburo, the latter now in the Kurokawa Institute of Ancient Cultures. Twenty-five works on record are signed against seventeen unsigned. Seventeen blades carry recorded provenance, through the Kishu Tokugawa house, the Shimazu of Sadowara in Hyuga, the Maeda, the Matsudaira, and the Meiji statesman Ito Miyoji, a noted lover of swords; one tachi retains an origami of Shotoku 2 (1712) by Hon'ami Kochu valuing it at thirty gold pieces. The National Treasure and the Important Cultural Properties are patrimony, preserved in the museum and shrine collections that keep them, Hie Jinja and Ise Jingu among the recorded institutional owners. What a private collector may realistically encounter lies in the thirty-two blades of the Tokubetsu Juyo and Juyo tiers, though most of recorded whereabouts are held privately or institutionally and seldom move; a signed Ayanokoji tachi comes to the market only rarely, and is a landmark for Yamashiro connoisseurship when it does.
