Suishinshi Masahide's earliest dated blade, of An'ei 6 (1777), is signed "Gorō Masahide" in homage to Gorō Masamune, and the published sources call that date "the oldest year they have seen". He was born Kawabe Gihachirō in Kan'en 3 (1750) at Akayu in Dewa. He first signed Suzuki Takahide and then Eikoku, studied under the Shitahara smith Yoshihide of , and is said to have entered the school of Tsunahiro as well. In An'ei 3 he took the name Masahide and the art name Suishinshi in the service of the Akimoto house of , and later he moved to Hamachō in . He trained many pupils and left many writings. His working life ran close to fifty years, from An'ei to Bunsei; in Bunsei 1 or 2, the sources differ, he took the lay name Tenshū, and he died in Bunsei 8 at seventy-six.
He is remembered as the theorist of the revival sword, who held that "all swords should return to the of old". The published sources are candid that his own best work came before that theory. Through the Tenmei, Kansei and Kyōwa years he modelled himself on the Ōsaka masters, tempering the surging of Tsuda Sukehiro or the of Inoue Shinkai, and "it is rather in this period that his masterpieces are found". Over a tightly packed that often tightens toward a plain, -like surface, thick adheres. The tōran builds a large into rolling waves from a long straight , with heavy , deep and a bright . His Shinkai manner is a broad deep in and , and a few blades follow Ikkanshi Tadatsuna. The finest come so close that the record says they "all but reach the original", and an early is called "an outstanding example of the so-called Ōsaka copy".
The published sources state with equal precision what still separates him from the originals. His blades tend to scant , "giving a flat feeling", and the point always tends to stretch. His is clean, yet "darkened coarse attach to it" and it comes "close to mekura-gane", the blind steel in which the does not show. Within the , too, coarse gathers here and there. On an Ikkanshi copy the commentary finds "blackish kazunoko- spilling over a -like forging, in which his habitual hand is seen". On a Sukehiro copy it is "coarse that mostly spills from within the into the ". The generally runs straight to a .
In his late years he put the theory into practice, and the published sources describe the result as a - that is shallow-tempered from first to last, with and work also attempted. One late - tempers a with abundant and a tight, bright , "the tempered without a flaw", yet with an at the that marks his hand; its tang records that his son Sadahide did the forging. Honma's inventory of the Imperial collection follows the change through three dated blades. A of Kansei 10, made at forty-eight, "is still a work in the Osaka manner", a large with a bright and thick . A of Bunsei 1 is unhurried, with especially fine , and the entry wonders whether it copies "Sadamune and the like". By Bunsei 2, at seventy, his work is mostly a mixed with , the tight in a over a -like . The carving of these years, the entry adds, is "almost all by his pupil Honjō Yoshitane".
Between the two phases the judges keep a clear order. Of the Kyōwa 3 recognised as a they write that the later work matters for sword history as a sign of its age, but "in quality the better pieces are rather found among the former". Of the revival they say plainly that "his technique did not reach that of his pupil Naotane". His own signature varies: the Kyōwa is cut in block script and also in cursive, and he used punning forms of the name. From Kansei 10 he stamped his tangs with a seal of the characters Nichiten worked into a sword shape. Its state of wear and repair dates a blade and helps sort true work from false, and the Bunsei 2 seal is "the last of the five seals of his lifetime". Among his pupils the published sources name Naotane and Hosokawa Morihide, the later second Masayoshi.
Masahide's record is entirely signed: twenty-four blades, one prewar and three blades in Honma's inventory of the Imperial collection, twenty-eight designated works on record. He has no National Treasure and no Important Cultural Property. The , dated Kyōwa 3 (1803), was held by the Shimogō Kyōsaikai of Shiga when it was recognised in 1941. The commentary prizes his , calling them "rare and valuable", and his blades made jointly with pupils, among them the tenth-generation Sendai Kunikane. Of a signed with Hosokawa Morihide it writes that "a joint work by the two is extremely rare and good material". Because his work is signed, dated and comparatively numerous, a Masahide is not beyond a private collector's reach. A example of his Ōsaka manner comes to market from time to time, and it carries the signed hand of the man who turned swordmaking back toward the old models.