Harumitsu signed his blades 治光 and styled himself Jirobei-no-jo, and the published sources place him by name within a documented line: the son of Jirozaemon-no-jo Katsumitsu and the father of Jurozaemon-no-jo Harumitsu, with dated work surviving across the Eisho, Daiei and Kyoroku eras of the early sixteenth century. He belonged to the workshops in their late- phase, the period the trade calls , when the smiths of the village worked in a shared idiom and signed with the day and month of their making. His own dated pieces are concrete: a of Daiei 5, a slender of Daiei 8, a broad of Daiei 4, a great of Kyoroku 2, and a of Daiei 7 made jointly with his father. Fujishiro rates him at the Jo- level.
His recognized hand is the waist-opened of the group. Over a wide, strongly -zori the published sources describe a broadly tempered with its bases opened, the pattern that gives the row its rhythm, mixed with slightly pointed elements and with faint appearing within the . On the slender Daiei 4 and on the joint that opened pattern breaks further, the temper heads splitting to form the the sources name as the structure peculiar to the group, with and and running through. It is a quieter, more legible version of the that the Sukesada masters were carrying to a brilliant pitch in the decades, and it is the first thing by which his blades are known.
The forging is an , on the broad and the standing in the grain with adhering, on the finer blades a packed tightly and thoroughly consolidated, mixed at times with . The carries the fullest work of all, its thick and entering, the large richly covered with so that and appear, gathers in places, enters and the is tempered. The follows the temper: a turning back, on the broad deeply with a at the point and an -like return, on the in , on the with a pointed tendency. There is no in his work, and the rests instead on the opened , the tightly forged steel and the that gathers most strongly on his fullest blades.
The published sources draw more than one face within this single hand. On the broad Daiei 5 they read the -opened as abundant in variation and, with the blade's good preservation, call it 「同作中の出色の一口」, an especially outstanding example among the smith's works. On the slender Daiei 4 they find the temper of a smaller pattern than is typical for him and note that it 「応永備前風が遺存」, preserving something of the older Oei- manner, so that the slim, -like reaches back a century into the past. The Daiei 8 shows yet another facet, a broad in which are engaged, its strongly felt, which the sources call 「地刃健全な治光の佳作」, a fine work of Harumitsu sound in both and . The of Kyoroku 2 carries his boldest intention, and the sources observe that he also made of broad width and emphatically flamboyant temper, so that the two together let one glimpse the aim behind his style.
Harumitsu is best understood beside his father. The joint 's commentary counts Katsumitsu among the most skillful masters alongside Munemitsu and Tadamitsu, and singles him out as the smith who 「互の目の中に丁子を交えて一段と華やかな出来口」, mixing into the for a distinctly more florid and brilliant result than the plainer compound general to the group. Harumitsu works within that broader group manner rather than at his father's most ornate pitch, but the published sources judge the great , in and alike, a typical example of the output of the school, and they value the father-and-son joint signature as documentary material of its own. The sources record that large are not infrequently met with in , the famous one being the piece Katsumitsu forged with Yosaburozaemon-no-jo Sukesada for Ukita Noie, the lord of , which sets Harumitsu's own stout within a recognized local type.
Harumitsu's surviving designated record is small and entirely signed, five blades among the Important Sword sessions from the 27th through the 44th, with no National Treasures among them, and a designation factor that places him in the middle ranks of rather than at its summit. None carries a recorded provenance, and only one has a holder of record, an institutional collection. The blades range across the wide , the slender -zori that reads as a , the stout great and the signed with his father, so that the small body of work shows the full breadth of his forms. He is the kind of named hand a collector encounters from time to time rather than rarely, the joint Katsumitsu-Harumitsu the most documentarily interesting of the group and the great the most striking, the published sources reserving for the best of them the phrase 「末備前中傑出の出来映え」, an outstanding level of workmanship among the works of .
