The Kaifu group (Kaifu-, 海部) takes its name from the Kaifu district of Awa Province on Shikoku, in the region of present-day Tokushima. The Meizukushi and the Kokon Meizukushi place the founder as Kaifu Tarō Ujiyoshi (海部太郎氏吉), set around the Kōryaku era (1379-1381), and record a second strand said to descend from a pupil of Naminohira around the era (1368-1375) who signed with the single character (藤). No blade securely traces back to those origins, and the are consistent that the group's documented activity belongs to the period, growing conspicuous from its latter half. The smiths who appear by name on the designated blades are Ujiyoshi (氏吉), Ujishige (氏重), Yasuyoshi (泰吉) with a Daiei 5 (1525) example, and Yasunaga (泰長), placed around the Daiei era; one by Ujishige is read as the earliest of the line, end of into early . A continuation survives in Fujiwara Ujiyoshi of Kaifu in Ama district, working in the Kyōhō era (1716-1736), whose hand the describes as late in appearance, his ancestors' manner carried forward without absorbing other provinces' shifts.
Forging across the group runs to or that often flows and inclines toward near the edge, with and that the repeatedly call subdued or lacking strong brilliance; and a faintly blackish recur. The temper is most often a base, from a narrow line on the to a broad mixed with , , and , the frequently hazy and oceanic (bōyō) rather than tight, with , , and ; turn back in with long or run with a tendency. The signature Kaifu form is the of wide and slight , carrying a with and cut as deep kaki-nagashi grooves, the long boldly chiselled in thick strokes. The also note the known as Kaifu mountain swords (Kaifu no yamatō), and a high, thick build of utilitarian character; a flowing -tinged with hazy temper and a coarse, bōbō reads as the group's ordinary signature, while finer pieces in the idiom step above it.
For , a deeply tempered -based blade whose carries dense can at a glance suggest Go Yoshihiro, and the group's drift toward a Naminohira manner and the old saying that Kaifu work "changed into E" mark the lines along which it is read. The standing of these smiths rests on cutting character: the Iwakiri Kaifu, a by Ujiyoshi recorded in the Kyōhō Meibutsu-chō, takes its name from its sharpness, was held by the Miyoshi of Awa with whom Miyoshi Nagayoshi is said to have won martial exploits, and passed thereafter to the Kuroda of Fukuoka. The Ujishige once in the collection of Miyoji is published in the Kōzan ; a by the later Yamato Daijō Ujishige stands at Hiromine Shrine; and two by Fujiwara Ujiyoshi were given to the Imperial Household Agency by volunteers from Tokushima. Signed Kaifu blades are few, which makes each named example reference material for the group as a whole.