Flowing Light – Hand Forged Carbon Steel Katana Sword

Flowing Light – Hand Forged Carbon Steel Katana Sword

Most katana blades are finished in one of a small number of ways: bright polish, stone finish, or black. The 流光 – Flowing Light – takes a different route. The blade surface is treated through a controlled bluing and polishing process that produces a deep, shifting blue tone across the steel – a colour that reads differently under warm light versus cool light, and changes again when the blade moves. It is this surface treatment, applied over the shinogi-zukuri ridgeline geometry, that gives the piece its name.

Specifications

The Steel

The designation 上色研考蓝 describes a surface colouring and polishing process applied to the carbon steel blade – a blueing technique that converts the outermost layer of the steel surface into a blue-black oxide, then polishes that surface to a controlled sheen. The result is not a paint or coating in the conventional sense. It is a chemical change to the steel surface itself, producing a colour that sits in the blade rather than on top of it.

The shinogi-zukuri ridgeline runs the full 72 cm blade length and creates a clear division on the flat – the two planes of the blade catch light at slightly different angles, meaning the blue tone reads as two subtly distinct shades depending on the viewing angle. On a wall mount, this gives the blade visual depth that a single-finish blade does not have.

The Feel of It

The 27 cm cotton ito-wrapped handle sits against the blue blade and the green aohada saya in a colour palette that is coherent and considered – cool steel blue, natural green bark, and the matte grey of the zinc alloy fittings. None of these colours compete. The cotton ito wrap is diagonal cross-laced in the traditional pattern, firm and even, and the sheath fits the blade with a clean, quiet draw. At 103 cm total length, the piece displays well horizontally, and the blue blade surface photographs with a depth that changes with the light source used.

Maintenance Notes

The blued surface provides modest corrosion resistance but should still be maintained with a light application of choji or mineral oil every few months. Avoid abrasive cloths – wipe only with soft microfibre or cotton to preserve the polished oxide surface. Do not attempt to sharpen or re-grind the blade, as this will remove the blueing treatment.