Awataguchi Kunitsuna worked in early Kamakura Kyōto as the youngest of the six Awataguchi brothers, the eldest being Kunitomo, and he styled himself Tōroku Sakon. The published sources transmit that he later went down to Kamakura, summoned by the Hōjō, and there, together with Kunimune and Sukezane of Bizen, became one of the smiths who opened the way for the Sagami tradition. They also concede how little of his hand survives: genuine signed works that can be accepted with confidence are recorded as extremely few[[c:1]], the celebrated Onimaru Kunitsuna standing as the representative piece. He worked under the name 国綱, and a long ōdachi survives signed in full 鎌倉住藤六左近国綱 and dated 建長五年八月日, the only dated trace of the Kamakura years.
The published sources draw a sharp line between him and the rest of the school. Awataguchi work is generally an earnest, classical elegance, but his shape, his forging and his temper are called distinctive: a tachi with high koshizori that does not droop toward the tip, a forging in which the itame stands large and prominent over thickly laid ji-nie, and a wide, varied temper in which the ha-nie is conspicuously strong[[c:2]]. The way both ji and ha are vigorously animated, the sources say, is precisely the hallmark of his art[[c:3]]. This is the recognition core: where his brothers refine, Kunitsuna pushes the nie forward, and the steel leans toward the bold Sagami manner that was about to be born.
Over that jigane runs a suguha base in shallow notare, mixed with ko-midare, chōji and ko-gunome, with thick ashi and yō, the nioi deep and the interior of the ha thickly covered in nie; kinsuji run frequently, sunagashi hangs, and in places the habuchi shows hotsure with uchinoke and yubashiri. The jigane is the tight Awataguchi steel carried thick with ji-nie and chikei, often standing into ō-itame, with a mizukage rising from the togidame that connects into a jifu-utsuri-like midare-utsuri, an aspect the sources note as often seen in his work. The bōshi is where the older profile had to be corrected: it is not simply a calm ko-maru. On the Tokubetsu-Jūyō tachi it runs straight into a ko-maru with a slight kaeri and the point sweeps a little hakikake[[c:4]], and on the kinzōgan-mei katana it sweeps straight in hakikake toward a yakizume tendency[[c:5]]; elsewhere it enters midarekomi with a pointed turn. That swept, nie-broken point is as much his tell as the standing grain.
The published sources are explicit that he has two faces. There are pieces in the orthodox Awataguchi manner, and there are works of a different cast, robust in form with a standing jihada[[c:6]]. The Onimaru belongs to the second, robust group; many of the surviving signed tachi belong to the first, where the forging tightens to a finer ko-itame, the temper a calmer suguha base, the whole quieter and more obviously of the court tradition. For the kantei eye the two faces share the same engine: the conspicuous ha-nie, the busy kinsuji and sunagashi, the midare-utsuri, and the swept hakikake bōshi. The subdued, sunken nioiguchi on the quieter tachi parts him from bright Bizen; the openly strong nie and the standing grain part him from the orthodox Awataguchi suguha of his brothers.
The Onimaru is the heart of his fame and the reason a smith of so few blades is known to every collector. Its later transmission reads as a history of power, passing through the great houses and into the Imperial collection, where it survives as an Imperial heirloom and one of the Five Great Swords, shown to almost no one. The published record names, beside it, a Tokubetsu-Jūyō tachi once held by the Viscount Nishitakatsuji family and an Important Art Object once owned by the Aizu Matsudaira house, and counts among the Important Cultural Properties attributed to him the tachi preserved at Hie Shrine. The kinzōgan and kinpun attributions on several of the shortened katana, cut by Hon'ami Kōson and his line, show how seriously the Hon'ami house took a Kunitsuna ascription.
For the collector this is among the rarest of the Awataguchi names. Fujishiro grades him Sai-jō saku, and his finest signed work descends through houses of the first rank: the Tosa Yamanouchi family held one kinzōgan-mei katana, and the Sendai Date family received another tachi from Konoe Motohiro and kept it as a treasured heirloom. A handful fall in the Tokubetsu-Jūyō and Jūyō tiers, with a small body of Important Cultural Properties, while the masterpiece itself can never leave the Imperial collection. A signed Kunitsuna in private hands is therefore one of the scarcest things a student of the early Kamakura sword can hope to meet, and the very scarcity is part of why his Sagami descent, by tradition the bridge that ran on to Shintōgo Kunimitsu and the Sōshū line, carries the weight that it does.
