The name Kuninaga appears across several distinct lineages and provinces spanning from the Nanbokucho through the Muromachi period. Among the most notable is the Uda school Kuninaga, whose lineage traces its origin to the late-Kamakura smith Konyudo Kunimitsu. In the Nanbokucho period, smiths such as Kunifusa, Kunimune, and Kunitsugu were active, and the school flourished through the end of the Muromachi period. Reference works enumerate four Uda smiths bearing the name Kuninaga, active from the Eikyo era through the Tensho era, though extant examples are rare. Separately, Sugawara Kuninaga, who resided in Kyoto in the mid-Nanbokucho period, is said to have belonged to the same lineage as Heianjō Mitsunaga of the late Kamakura period, and his surviving signed works are extremely few. A further Kuninaga worked in Noshu (Mino Province), recorded in compendia as active in the Oei and Bunmei eras.

The Uda school Kuninaga displays the characteristic technical hallmarks of his tradition. The jigane is itame mixed with mokume, with overall hada-dachi, ji-madara, and conspicuous shirake-utsuri -- features that express a strong Yamato character rooted in the school's origins in Uda District of Yamato Province. The hamon is a shallow notare mixed with ko-gunome and ko-togariba, with well-adhering nie and prominent kinsuji and sunagashi. In the best works, the upper half intermixes tobiyaki and yubashiri, presenting a somewhat hitatsura-like tendency that surpasses the school's usual manner in spirited, forceful presence -- revealing the Soshū-influenced strand that also runs through Uda production. Sugawara Kuninaga of Kyoto, by contrast, shows a Yamato-like temperament in the manner of Mitsunaga: hada that flows and tends toward masame, suguha with a tight nioiguchi and ko-nie, slight hotsure along the habuchi, and boshi with hakikake.

Across these distinct Kuninaga traditions, surviving signed works are uniformly scarce and hold high documentary value. The Uda Kuninaga wakizashi with its large-scale taihai and hitatsura tendency constitutes an exceptional example that transcends the school's ordinary output. Sugawara Kuninaga's tachi bearing an Enbun-era date is precious both as a rare signed work and as corroborating evidence for the transmitted lineage linking him to Mitsunaga. The Noshu Kuninaga wakizashi, appraised as no later than the Nanbokucho period despite later dates recorded in compendia, shares elements in common with Nobukuni and is kenzen in both ji and ha. Together, these works illuminate the breadth of production carried out under the Kuninaga name across multiple provinces and traditions.