Katana Spring Ember Oroshigane Kobuse Blade Sakurai Mokko Koshirae 春霞

Folded Oroshigane Steel Shinken (真剣) | Spring Ember  Katana: TangGu (湯谷) Oroshigane (卸し金) Kobuse Blade (甲伏造) + TangGu (湯谷) Sakurai Mokko Koshirae (桜影拵)

This katana brings together the refinement of traditional craftsmanship and the structural integrity required for practical use. The blade is forged from in-house refined Oroshigane (卸し金) steel in Kobuse-zukuri (甲伏造) construction, featuring a hard outer layer wrapped around a softer core—an approach shared with classical tamahagane swords to achieve both durability and resilience. Folding produces a mixed Mokume-hada and Masame-hada grain pattern (杢目肌・柾目肌交じり), while polishing reveals a lively Gonome-Midare hamon (互目乱刃文) formed through clay tempering (覆土焼入れ). The saya (鞘) is finished in Shuro Nuri lacquer (棕櫚塗), displaying a warm, organic brown surface with subtle fiber-like textures reminiscent of natural palm bark. The koiguchi, kojiri, and kurigata are reinforced with water buffalo horn. The tsuka (柄) features a brown tsuka-ito tightly wrapped over natural white samegawa (白鮫皮), with hishigami (菱紙) used throughout to achieve a secure wrap and crisp, even diamonds. The menuki (目貫) are crafted from white copper, blackened (煮黒), and adorned with elegant floral motifs (花卉文). The fuchi and kashira (縁頭) are also made of white copper, finished in black and decorated with raised sakura designs (櫻花浮雕). The tsuba (鍔) is a mokkō-shaped white-copper guard, blackened (煮黒仕上げ), and richly detailed with sakura relief carving (櫻花浮雕). The habaki (鎺) is forged from brass and engraved with the traditional Nekogaki cat-scratch pattern (猫掻).

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 mokkō-shaped tsuba crafted from white copper and finished in a deep blackened patina (煮黒仕上げ), decorated with raised sakura motifs (櫻花浮雕).
• Fuchi-Kashira (縁頭): White-copper fittings, blackened (煮黒), featuring finely rendered sakura relief carvings (櫻花浮雕).
• Menuki (目貫): White-copper menuki featuring delicate floral designs (花卉文).
• Habaki (鎺): A brass habaki engraved with the traditional Nekogaki (Cat-scratch / 猫掻) pattern.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin in a natural white finish.
• Handle Wrapping (柄巻): Brown cotton (or rayon) tsuka-ito, tightly wrapped over hishigami for clean, uniform diamonds.

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): Finished in Shuro Nuri lacquer (棕櫚塗), featuring a rich, organic brown surface with subtle fiber-like patterns that evoke the natural texture of palm bark. This warm, traditional finish gives the saya a distinctive depth and understated elegance.
• 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