A Rai Kunitsugu Katana (来国次)

Rai Kunitsugu (来国次) is believed to have studied under Rai Kunitoshi and was likely a cousin of Rai Kunimitsu. Within the Rai School he is the smith who most emphatically placed nie at the forefront of his work – so much so that he was traditionally counted among the Ten Students of Masamune and referred to as Kamakura-Rai (鎌倉来). The NBTHK notes, however, that the relationship was more likely one of deep admiration at a distance than direct tutelage: Kunitsugu absorbed the Sôshû influence and pushed the Rai tradition in a more powerful, nie-intensive direction that set his work apart from all his contemporaries. Existing long swords are exceptionally rare; the great majority of his surviving output consists of tanto and ko-wakizashi, making a fully attributed katana of this calibre genuinely uncommon.

This blade carries the imposing shape of the late Kamakura period: a relatively wide mihaba with no noticeable taper, a koshizori that deepens towards the tip, a somewhat elongated chû-kissaki, and generous hira-niku that gives it a robust and weighty feel. The kitae is a standing-out itame mixed with mokume, packed with fine ji-nie and much fine chikei, with a faint nie-utsuri moving through the ji. The hamon is a nie-laden chû-suguha-chô with a brilliantly bright nioiguchi, enlivened with gently undulating notare, ko-chôji, and ko-gunome, with many ashi and yô, and fine kinsuji and sunagashi throughout. The bôshi is a gently undulating notare-komi with fine hakikake and a ko-maru-kaeri. Both ji and ha are in strikingly healthy condition.

The shirasaya carries inscriptions of exceptional distinction. The sword scholar Satô Kanzan inscribed his attribution in January 1970, praising the blade as a gorgeous work by one of the Ten Students of Masamune – and the admiration of Nakamiya Kei’ô (中宮敬翁), who added his own inscription at the age of 82, adds further weight to this assessment. Tanobe Michihiro (Tanzan-sensei) then inscribed a full sayagaki in November 2025, confirming the attribution to Rai Kunitsugu with characteristic authority and noting the blade’s intense nie emphasis, robust and magnificent shape, and strikingly healthy condition. A custom koshirae is currently being made for this sword by Unique Japan.