Wrought Iron Yoroidoshi Sculpture – Crossed Heart Forge

A forging exercise leading to a sculptural tanto form for study and enjoyment, part of the Artist in Residence project at the museum. Forged from a piece of lovely fine-grained salvaged wrought iron railroad plate more than a century old. A little large for opening letters, this piece would function as a collectible, art object, paperweight, and conversation piece. An excellent extension of kata work for students but with the addition of being a tactile three-dimensional study of a tanto form.

Island Blacksmith: Charcoal forged knives from antique steel.

Crafted entirely with hand tools and traditional techniques, the slender blade profile and thick spine are based on a classical yoroidoshi (鎧通し, armour piercing) tanto design. The lovely proportions of this piece are an interpretation of a famous national treasure tanto known as the mouritoushirou, though the tang is a slightly different style. Wrought iron has almost no carbon and will not take or hold a particularly fine edge so this work is designed to be enjoyed as is, straight out of the forge. Unmounted.

Island Blacksmith: Charcoal forged knives from antique steel.

Construction is muku with hira-zukuri profile and mitsu mune. The blade dimensions are 10.5″ (265mm) long and just over 7/8″ (28mm) by 5/16″ (7.5mm) at the mune machi. From the tip to end of the tang is about 14.75″ and the edge is about 1mm thick just as it would be after yaki-ire. Grey iron hammer texture forge finish with a light coat of oil.

Specifications

長さ/刃長 Nagasa / blade length: 8 sun 8 bu (265mm)
重ね/元重 Motokasane / spine thickness: 2 bu 5 rin (7.5mm)
元幅 Motohaba / blade width: 7 bu 5 rin (23mm)
反り Sori / spine curve: 2 rin (1mm)
中心/茎 Nakago / tang length: 3 sun 6 bu (110mm)

形 Katachi / geometry: hira-zukuri, mitsu-mune, as-forged
刃文 Hamon / edge pattern: none
帽子/鋩子 Boshi / tip pattern: none
中心/茎 Nakago / tang: futsu, kuri-jiri, no mekugi-ana
銘 Mei / signature: mumei (unsigned)
拵 Koshirae / mounting: none

Materials: Reclaimed antique wrought iron rail plate

Island Blacksmith: Charcoal forged knives from antique steel.

Process

This piece was forged at the museum forge. It began as a pre-1900s railway plate made from fine wrought iron.

This rail plate came from a railway that was abandoned before 1926 and is made from wrought iron over a century old.

A break test can confirm wrought iron or layering as well as indicate the level of carbon in a piece of scrap.

The way the layers bend and break shows a finely layered wrought iron texture.

The traditional charcoal swordsmithing forge lit in preparation for this project.

The starting point as an unusually shaped piece of rare scrap iron.

Multiple heats and careful hammering were required to straighten the piece and draw it out into a bar.

The sunobe preform allots the volume of steel in proper proportions before hizukuri (bevelling) begins.

During the hizukuri stage the triple-faceted mitsu-mune spine is forged in first, followed by the bevels.

Clay mixture is applied after some final adjustments with hammer and some filing to establish the notches and clean up the spine.

Even though the iron does not have enough carbon to harden, yaki-ire is performed to document the complete process and adjust the spine curvature.

Cleaned up after yaki-ire, the blade has a lovely form and retains its hammer textured surface.

Water forging has kept much of the fire scale off, leaving the surface with a natural texture.

Island Blacksmith: Charcoal forged knives from antique steel.

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