In Shoo 2 (1289), Sanemori signed a with the long inscription no junin Sama no jo Sanemori , adding the yotsume-bishi crest and, a rarity for him, a date. Dated works of the Kenji, Koan and Shoo eras (1275 to 1293) survive, and the published sources state plainly that "his period of activity is clear." He is held to be the son of Moriie, by other accounts his pupil or grandson; it is also suggested that he served as one of Moriie's smiths, which would explain the scarcity of his own signed blades. Neither Moriie nor Sanemori ever signed -ju, the residence in the always reading , so is understood as a hamlet within village. His dated pieces fall in precisely the years of Nagamitsu, and that position, between his father's flamboyance and the composure of the mainline, is the axis on which everything written about him turns.
His prime manner is a laced with -, the pinched-waist tadpole in which, the published sources write, the smiths were "skilled as a specialty". What separates him from the father is scale. The 's standing formula for him, repeated in more than twenty of his texts, runs: "compared with Moriie, the generally tends toward a somewhat smaller pattern". The clusters sit a degree smaller, the rise and fall of the is less pronounced, and the tadpole heads often show plainest on the side. and mix into the , and enter richly, and the temper is -primary with , the described again and again as bright. and work through the with small in places, and the runs or settles in , often with a pointed tendency and light .
The carries the school's tell. He forges mixed with that tends to stand, with fine thick and , under a vivid ; on the dated Shoo the takes a mottled, -like state. The standing tendency is milder than in Moriie yet stronger than in the smiths. Beside it a second class of forging exists, a tightly knit of great refinement; of one such blade, formerly of the Saijo Matsudaira family of Iyo, the writes that it is "the finest among works attributed to this smith". A school point shows in the as well: compared with Mitsutada and the smiths, the tends to extend, and his keep a high with .
The published sources sort his work into three manners: the flamboyant , mixed with , and a class, the latter two generally quieter than the father throughout. The divides along the line. Most blades carry a two-character signature in one of two cuttings: the bold cutting yields flamboyant works resembling Moriie, while the small cutting is "generally close to Nagamitsu and Kagemitsu". The largest-signed and most flamboyantly tempered he had seen, Honma Junji judged "without doubt the work of the first generation". Long signatures bearing the office title are rare and appear as both Sama no jo and Uma no jo; the Uma no jo carries a with shallow , the rare signed a with a . Behind the two cuttings lies a deeper question: "it is thought there were two generations of the name, but distinguishing them by the characters of the is at present difficult." The name itself demands care, for smiths signing Sanemori existed in -period Hoki at Ohara and among the -period ; the notes that "their and workmanship of course differ in each case."
At his best the question is no longer his father but itself. The dated Shoo 2 , the published sources write, "at first glance calls to mind a superior work of Nagamitsu", and only the slightly standing gives the line away. On rank the sources are frank: "on the whole he does not reach Moriie, and the especially falls short". Yet the smaller pattern and gentler rise and fall that keep him below the father are what carry his quieter blades toward the masters. Unsigned attributions therefore rest on his own combination: the tadpole-laced over a slightly standing under vivid , the whole one degree calmer than Moriie. In one case the appraisal was settled because the shape closely matches his extant signed work. Surviving signed are relatively few, and the published sources note that no has been seen.
Fujishiro rates him Jo-jo , and fifty-seven designated works stand on record. There are no National Treasures among them, but six blades are Important Cultural Properties, one transmitted in the Asano family of Aki, and five are prewar Bijutsuhin, once held by collectors such as Kuroda Nagamichi and Kurokawa Fukusaburo. Five blades hold the rank and forty-one the , forty-six in the two tiers together. His blades passed through the Kishu Tokugawa family, the Shimazu of Satsuma, the Saijo Matsudaira of Iyo, and the Mori, Kuroda and Maeda houses. Of recorded whereabouts today, examples rest in collections including the Kyushu National Museum, the Hayashibara Museum of Art and the Kurokawa Research Institute. For the collector he is more approachable than the great names yet still a smith of patience: most of what circulates is , resting on the smaller-patterned tadpole , and such a blade appears only from time to time. A signed piece is another matter. The two-character are few, the long-signed and dated works fewer still, and when one of the latter changes hands it is an event, carrying as it does the residence, the office title and the year in the smith's own hand.