A Rai Kuniyasu Katana (来国安)

This katana is the work of Rai Kuniyasu, a swordsmith originally from the renowned Rai school of Yamashiro province (Kyôtô). Said to be the grandson of Rai Kunisue, Kuniyasu departed Kyoto in 1337 at the outset of the Nambokuchô period – when the capital was engulfed in civil war – in search of pure water to forge his blades. He eventually settled in Echizen province (modern-day Fukui prefecture) along the Sea of Japan and founded the Chiyozuru school, a name drawn from his childhood nickname Chiyozurumaru, meaning ‘a thousand generations of cranes’ – a symbol of longevity deeply rooted in Japanese culture.

The blade commands attention immediately. Its wide mihaba extends the full length without taper, and a substantial koshizori – curvature concentrated at the waist – lends it a majestic, powerful silhouette that is entirely characteristic of the mid-Nambokuchô period. Despite being ô-suriage (greatly shortened), the blade has retained most of its impressive curvature, which extends into the nakago itself. The ô-kissaki is original – a rarer survival for a sword of this age, as many tips from the period were reshaped after battle damage.

The jigane carries the dark, brooding tone typical of Echizen-forged blades, with a standing-out itame mixed with mokume and nagare, enriched throughout by fine chikei. Against this dark ground, the bright chû-suguha hamon shines with clarity – nie-laden, with a brilliant nioiguchi, fine nie-hotsure, delicate ko-ashi, and threads of kinsuji and sunagashi working through the temper. The boshi is a gently undulating notare-komi with a ko-maru-kaeri and sweeping hakikake. The healthy width of the blade – retaining ample distance between the hamon and the cutting edge – was a primary factor in its designation as NBTHK Jûyô Tôken at the 60th session.