Kuromon Aikuchi Tanto

Kuromon can be translated as “the black gate”. Designed around the concept of textural exploration as a companion project to Kuromatsu Aikuchi Tanto, this tanto with koshirae is a bold yet restrained piece that has the austere simplicity that appealed to the refined tastes of working samurai centuries before the Edo period.

This tanto is hand forged from reclaimed shear steel that was likely made before 1850, housed in an aikuchi koshirae crafted entirely with hand tools from local driftwood and finished with black urushi lacquer.

Materials for the koshirae came from Nootka Cypress driftwood, Oceanspray ironwood for the kurigata and koiguchi, forged copper bus bar for the habaki, and forged silver scrap for the mekugi. The exterior is finished with a charcoal polished natural urushi lacquer surface, selectively distressed and oiled to give the feeling of a long-carried and well-cared-for piece. The solid silver mekugi is shaped like an iron kugikakushi (釘隠), a large nail cover found on a traditional castle door or gate, and is a symbol of protection.

The blade was hand forged in a charcoal fire from a horse-drawn carriage leaf spring, shaped with files, differentially hardened using traditional water quench yaki-ire, and polished by hand with water stones. The unusual polish shows a very strong hada, revealing the blistery texture and flowing layers of the forge-welded shear steel. A classical polish can be arranged upon request. Blade construction is muku with a hira-zukuri profile and an iori mune. The blade is approximately 7.75″ long, overall length is around 12.5″, and the overall length when sheathed is about 14.5″. Accompanied by a handcrafted reclaimed Black Walnut display stand and a hand stitched reclaimed silk obi storage bag.

See photos of the process of making this tanto and koshirae here: Process: Making the Kuromon Aikuchi Tanto

Specifications

長さ/刃長 Nagasa: 6 sun 5 bu 2 rin (197mm)
元幅 Motohaba: 8 bu 5 rin (25mm)
重ね/元重 Motokasane: 2 bu (6.5mm)
反り Sori: 3 rin (1mm)
中心/茎 Nakago: 3 sun 4 bu 5 rin (104mm)
柄長 Tsuka: 3 sun 7 bu (111mm)
拵全長 Koshirae: 1 shaku 2 sun 3 bu 5 rin (374mm)

形 Katachi: hira-zukuri, iori-mune
刃文 Hamon: suguha, double “kimono” mizukage
帽子/鋩子 Boshi: ko-maru
中心/茎 Nakago: futsu, kuri-jiri, one mekugi-ana, signed near the tip
銘 Mei: hot stamped katabami-ken kamon
拵 Koshirae: kuro nuri aikuchi, issaku

Materials: Century-and-a-half-old horse carriage spring shear steel, copper electrical bus bar, silver scrap from local miners in the Congo in the ’80s, driftwood Nootka Cypress, Oceanspray island ironwood, natural urushi lacquer

This piece is in a private collection in Texas.

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques

Process

Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques
The raw material for this blade spent more than the last century as a leaf spring for a horse-drawn carriage. It is rare to come across this type of steel and is a treasure to find. It is a type of steel called “shear steel”, predating the bessemer process and blast furnaces. The deep pitting on the surface from decades of weather will mean a lot of polishing time and less steel to work with so forging must be done very accurately.
Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques
Immediately after hardening, before tempering. It has acquired a small amount of curvature from the tension between the two different types of steel crystal formation now making up the blade.
Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques
After the insides are carved and the split block rejoined with rice paste glue, the outside is shaped by carving. The corners are removed, and then their corners are removed in turn, carefully removing the excess wood until the final form emerges.
Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques
The koshirae parts before assembly. The finished kurikata fits snugly into a channel cut into the saya. It will be attached permanently with sokui and nori-urushi, an adhesive made from rice paste, water, and natural urushi lacquer.
Island Blacksmith: Charcoal forged nihonto made from reclaimed and natural materials using traditional techniques
Natural urushi lacquer is applied in thin layers, water polishing with charcoal and curing for several days each time. It is then given a fine matte polish with tokusa, horsetail grass, which contains fine silica in the plant cells. The final layers are built up with pure flax and tung oil applied and burnished directly with the hands as if in regular use over time.

Detailed accounts of various stages of the process are documented here: Making the Kuromon Aikuchi Tanto

3.03022 cm
= 0.1 shaku(尺)
= 1 sun(寸)
= 10 bu(分)
= 100 rin(厘)

Comments are closed.