Katana Tidal Dragon Oroshigane Kobuse Blade Tōryū Koshirae 潮龍

Folded Oroshigane Steel Shinken (真剣) | Tidal Dragon Katana: TangGu (湯谷) Oroshigane (卸し金) Kobuse Blade (甲伏造) + TangGu (湯谷) Tōryū Koshirae (涛龍拵)

This katana (打刀) features a blade forged from in-house refined Oroshigane (卸し金) steel in Kobuse-zukuri (甲伏造) construction — a hardened outer jacket surrounding a softer core, achieving both strength and resilience. The surface reveals an elegant Ayasugi-hada (綾杉肌) pattern, resembling flowing cedar grains with rhythmic waves. A calm and straight Suguha hamon (直刃刃文) emerges through traditional clay tempering (覆土焼入れ), reflecting precision and inner discipline.

The saya (鞘) is finished in palm bark-style lacquer (棕櫚塗), presenting a warm, natural texture with understated depth. The kojiri, koiguchi, and kurigata are crafted from buffalo horn. A golden silk sageo (黄絹下緒) is woven in traditional style, complementing the earthy tones of the scabbard.

The tsuka (柄) is wrapped in brown silk ito (茶色絹糸) over aged ivory samegawa (鮫皮), reinforced with hishigami (菱紙). The menuki (目貫) are white copper sword dragons (剣龍), finished with blackened patina (煮黒仕上げ), symbolizing valor and protection. The fuchi and kashira (縁頭) are brass fittings engraved with wave and dragon motifs (涛龍図), completed with a refined blackened patina. The tsuba (鍔) is a round brass guard, hand-carved with a wave and dragon design (涛龍片切彫), finished with a deep black patina for a dignified, timeless presence.

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 71 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): Ayasugi-hada（綾杉肌）— cedar-grain pattern with alternating waves.
• Temper Line (Hamon 刃文): Suguha（直刃刃文）— straight temper line formed by clay tempering.

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 outer steel shell surrounding a softer core for optimal strength and resilience. Traditional folding reveals an elegant Ayasugi-hada (綾杉肌) grain, resembling flowing cedar patterns with alternating waves. Polishing brings out a calm and straight Suguha hamon (直刃刃文), created through precise clay tempering (覆土焼入れ), along with a well-defined ridge line (Hōmi / 峰).

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Brass tsuba hand-engraved with wave and dragon (涛龍) motif in katakiribori (片切彫) style, finished with a deep black patina (煮黒仕上げ).
• Fuchi-Kashira (縁頭): Matching brass fittings featuring wave and dragon carvings (涛龍図), completed with a refined blackened patina (煮黒仕上げ).
• Menuki (目貫): White copper menuki depicting sword dragons (剣龍), finished with blackened patina.
• Habaki (鎺): Hand-forged brass with an aged finish.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin aged to a soft yellow hue.
• Handle Wrapping (Tsuka-maki 柄巻): Brown silk ito (茶色絹糸), 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): Palm bark-style lacquer (棕櫚塗), featuring a textured matte brown finish that evokes the natural pattern of palm bark.
• Sageo (Cord 下緒): Golden silk sageo (黄絹下緒), woven in traditional style.

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