Katana Sakura Radiance Oroshigane Kobuse Blade Kōei Koshirae 櫻輝

Folded Oroshigane Steel Shinken (真剣) | Sakura Radiance Katana: TangGu (湯谷) Oroshigane (卸し金) Kobuse Blade (甲伏造) + TangGu (湯谷) Kōei Koshirae (光映拵)

This uchigatana is forged from in-house refined Oroshigane (卸し金) steel, using Kobuse-zukuri (甲伏造) construction in which a hardened outer layer encases a softer core, the same principle employed in traditional tamahagane blades to achieve both sharpness and resilience. Repeated folding produces a flowing Masame-hada (柾目肌) grain pattern that stretches elegantly along the blade. Careful polishing reveals a refined Suguha Hamon (直刃刃文), formed through clay tempering (覆土焼入れ), giving the blade a dignified and traditional presence. The saya (scabbard) is finished in Kin-nashiji lacquer (金梨子地塗), shimmering with fine golden reflections. Kojiri, koiguchi, and kurigata are made of buffalo horn for durability. A pale white silk sageo (浅白色正絹下緒) is tightly woven, while the tsuka (handle) is wrapped in pale white silk ito (浅白色柄糸) over genuine samegawa, reinforced with hishigami inserts. The fittings are crafted with fine detail: the menuki (目貫) are nickel silver with a blackened patina, depicting a sword-dragon (剣龍図) motif; the fuchi-kashira (縁頭) are nickel silver with blackened finish, engraved with delicate sakura patterns (桜文様); the habaki (鎺) is hand-forged from brass with an aged finish; and the tsuba (鍔) is a round nickel silver guard, finished in blackened patina (煮黒仕上げ), carved with sakura blossom sukashi (桜花透かし). Together, the koshirae embodies elegance and solemn refinement.

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: Designed for Iaido (non-sharpened), Kenjutsu, and Tameshigiri (test cutting) practice, as well as for collection, display, and appreciation by enthusiasts and connoisseurs.

Blade Specifications

• Blade Length (Nagasa刃長): Approx 73 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. 40 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), Ō-kissaki (Large tip 大切先)

• Forging Pattern (Hada 鍛肌): Masame-hada（柾目肌） — straight, linear grain pattern running along the blade, achieved through repeated folding and forging.
• Temper Line (Hamon 刃文): Suguha（直刃刃文） — a straight temper line formed by traditional clay tempering, emphasizing simplicity and refinement.

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 
• Key Features:

  • The blade is forged from in-house refined Oroshigane (卸し金) steel using Kobuse (甲伏) construction — a hard steel jacket surrounding a softer core for resilience. Traditional folding reveals a Masame-hada (柾目肌) straight-grain pattern, while careful polishing brings out a refined Suguha Hamon (直刃刃文) formed through clay tempering, along with a well-defined ridge line (Hōmi / 峰).

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Round shaped copper-alloy tsuba (白銅丸形鍔) with a blackened patina (煮黒仕上げ), featuring sakura blossom sukashi (桜花透かし) cutouts.
• Fuchi-Kashira (縁頭): Copper-alloy fittings with a blackened finish, delicately engraved with sakura motifs (桜文様).
• Menuki (目貫): Copper-alloy menuki finished in blackened patina, depicting sword-dragon (剣龍図) designs.
• Habaki (鎺): Hand-forged brass with aged finish.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin aged to a soft yellow hue.
• Handle Wrapping (Tsuka-maki 柄巻): Tightly wrapped in pale white silk ito (浅白色正絹柄糸) in traditional style.

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): Kin-nashiji style lacquer (金梨子地塗り) — a glossy golden pear-skin finish that sparkles with fine metallic reflections.
• Sageo (Cord 下緒): Pale white silk sageo (浅白色正絹下緒), tightly woven in traditional style.

Measurements

• Blade Weight: Approx. 0.65 kg
• Sword Weight (without Saya): Approx. 1.0 kg
• Total Weight: Approx. 1.3 kg
• Overall Length: Approx. 100 mm