Katana Golden Plum Oroshigane Kobuse Blade Kinbai Koshirae 金梅

Folded Oroshigane Steel Shinken (真剣) | Golden Plum Katana: TangGu (湯谷) Oroshigane (卸し金) Kobuse Blade (甲伏造) + TangGu (湯谷) Kinbai Koshirae (金梅拵)

This katana brings together the elegance of traditional craftsmanship and the strength required for practical use. The blade is forged from in-house refined Oroshigane (卸し金) steel in Kobuse-zukuri (甲伏造) construction, with a hardened outer steel layer and a softer core — the same method used in tamahagane blades for balanced cutting and resilience. Traditional folding produces a mixed Mokume-hada and Masame-hada (杢目肌・柾目肌交じり) grain pattern, while polishing reveals a dynamic Gonome-Midare hamon (互目乱刃文) created through clay tempering (覆土焼入れ). The saya (鞘) is finished in glossy black Kin Ryūhen raden-style lacquer (金流変螺鈿塗), featuring flowing gold accents and subtle iridescent shell particles. Kojiri, koiguchi, and kurigata are crafted from buffalo horn. The tsuka (柄) is wrapped in yellow tsuka-ito over aged yellow samegawa (鮫皮), reinforced with hishigami (菱紙). The menuki (目貫) are made of white copper and feature delicate floral designs (花卉文). The fuchi and kashira (縁頭) are white-copper fittings engraved with flowing karakusa motifs (唐草文). The tsuba (鍔) is a round iron guard with an openwork plum-tree motif (Ume Sukashi / 梅樹透鐔), completed in a traditional blackened patina (煮黒仕上げ).

TangGu (湯谷) Oroshigane Kobuse Blade

This blade is hand-forged (Tezukuri / 手作り) from in-house refined Oroshigane (卸し金) steel, smelted from satetsu (砂鉄) and repeatedly folded (orikaeshi-tanren / 折り返し鍛錬). Forged in Kobuse-zukuri (甲伏造) construction, this Oroshigane shares the same forging lineage as traditional Tamahagane (玉鋼), achieving comparable performance and structure while allowing the smith to refine the steel’s properties by hand.

Blade Forging Details

• Blade Name: TangGu Folded Oroshigane Kobuse Blade (甲伏造)
  

• Forging Method: This blade is forged in Kobuse-zukuri（甲伏造）style, with a hardened outer layer over a softer iron core. It is differentially hardened using clay tempering（覆土焼入れ）, producing a sharp edge, resilient spine, and a visible hamon（刃文).

• Materials: Oroshigane (卸し金) steel smelted from satetsu (砂鉄), refined in-house using traditional methods（伝統的手法による自家製鋼材）

• Purpose: Suitable for Kenjutsu and Tameshigiri (test cutting) practice, collection, and display. Unsharpened blades are available for Iaido upon request.

Blade Specifications

• Blade Length (Nagasa刃長): Approx 69 cm
• Tang Length (Nakago 茎長): Approx. 24 cm
• Width at Base (Motohaba 元幅): Approx. 31 mm
• Thickness at Base (Motokasane 元重): Approx. 6 mm
• Width at Tip (Sakihaba 先幅): Approx. 22 mm
• Thickness at Tip (Sakikasane先重): Approx. 4 mm
• Kissaki Length (Tip 切先長): Approx. 37 mm
• Mekugi-ana (Peg Hole 目釘穴): 1

Blade Characteristics

• Shape: Shinogi-zukuri (ridged blade 鎬造), Iori-mune (flat ridged spine 庵棟), Chū-kissaki (Medium-sized tip 中切先)
• Forging Pattern (Hada 鍛肌): Mokume-hada mixed with Masame-hada（杢目肌・柾目肌交じり）— a composite pattern showing wood-grain swirls with straight grain elements, created through repeated folding and layering.
• Temper Line (Hamon 刃文): Gonome-Midare (互目乱刃) — a flowing, irregular temper line characterized by alternating rounded peaks, created through traditional clay tempering (覆土焼入れ).

Special Features and Workmanship

Hi (Groove) Engraving

• Type: Hi-Nashi (樋なし)
• Processing Range: None (No bohi) – Solid blade for added weight and strength

Polishing Work

• TangGu Polishing Levels:
  • Highest-grade shaping polish 最上・成形研磨 
  • Superior rough polish 最上・下研ぎ 
  • Detailed final polish 最上・仕上げ研ぎ 

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): A round iron tsuba with an openwork plum-tree motif (Ume Sukashi / 梅樹透鐔), finished in a blackened patina (煮黒仕上げ).
• Fuchi-Kashira (縁頭): White-copper fittings engraved with flowing karakusa motifs (唐草文).
• Menuki (目貫): White-copper menuki featuring delicate floral designs (花卉文).
• Habaki (鎺): Crafted from red copper (akagane / 赤銅) with a smooth – finish.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin aged to a soft yellow hue.
• Handle Wrapping (柄巻): Yellow cotton (or rayon) tsuka-ito, tightly wrapped with hishigami support.

Saya and Accessories

• Saya (Scabbard 鞘): Traditional-style design reinforced with water buffalo horn at the koiguchi (mouth), kojiri (end), and kurigata (cord knob).
• Saya Lacquer (鞘塗): A glossy black surface enhanced with flowing gold accents and subtle iridescent shell particles, creating a shimmering Kin Ryūhen (金流変) effect.
• Sageo (Cord 下緒): Japanese-made sageo available in multiple colors

Measurements

• Blade Weight: Approx. 0.65 kg
• Sword Weight (without Saya): Approx. 1.0 kg
• Total Weight: Approx. 1.35 kg
• Overall Length: Approx. 100 mm