From Yamato to Mino
According to Japanese Wikipedia, he was of the Tegai school (手掻派, Tegai-ha) of Yamato, where he was called 包氏 (Kaneuji), with a different character for “kane”; he learnt the Sōshū manner from Gorō Nyūdō Masamune and, on settling in the village of Shizu, in Mino, began to sign Shizu Saburō Kaneuji and formed the Shizu school. After his death, his followers moved to Naoe, and from there comes the Mino tradition. The Kotobank dictionaries place Shizu in the Tagi district, in Mino.
A pupil of Masamune?
He is among the ten pupils of Masamune (正宗十哲, Masamune jittetsu). Japanese Wikipedia qualifies that this list dates from the end of the Edo period, that not all ten were necessarily direct pupils, and that Kaneuji, who came out of the Tegai school, is seen as a pupil of Masamune.
The dates
In Kotobank, one dictionary gives his life as 1284 to 1343, and the Nihonjinmei Daijiten+Plus says that a work from his last years bears the date Kōei 2 (1343). That blade does not appear in any of the other sources consulted, and the dates of his birth and of his arrival in Shizu that circulate have no support in them.
The birth of the Mino tradition
The Japanese Sword Index, which summarises Nagayama, divides the school into two phases. Early Mino runs from the end of the Kamakura to the middle of the Nanbokuchō: Kaneuji, a pupil of Masamune who came from Yamato and joins the influence of Yamato to the jigane of Sōshū, and Kinju, who came from Echizen. Middle Mino is the Naoe-Shizu: Kaneyuki, a second Kaneuji, Kanetoshi, Kanetsugu, Kanetomo, Kanehisa and Kanenobu.