Katana Dragon Roar Kobuse Blade Ryūha Koshirae 龍吟

Clay Tempered Full Tang Shinken (真剣) | Dragon Roar Katana: TangGu (湯谷) Kobuse Blade (甲伏造) + TangGu (湯谷) Ryūha Koshirae (龍波拵)

This uchigatana-style koshirae（打刀拵）is made for collectors and martial artists. The blade is hand-forged in Kobuse-zukuri（甲伏造）construction, where a hardened outer steel jacket encases a softer inner core. Masame-hada（柾目肌）and Mokume-hada（杢目肌）patterns are visible on the surface, showing straight and swirling grain from repeated folding. A Gunome-midare hamon（互の目乱れ刃文）runs along the edge, created through clay tempering（覆土焼入れ）. The saya（鞘）is finished with dripping-gold lacquer（滴金塗り）and fitted with buffalo horn（牛角）at the koiguchi（口金）, kurigata（栗形）, and kojiri（鞘尻）. A green cotton sageo（緑色の木綿下緒）is tied at the side. The tsuka（柄）is wrapped in green cotton ito（緑色の木綿糸）using hineri-maki（捻巻）over aged samegawa（古風仕上げの鮫皮）. Hishigami（菱紙）form diamond patterns under the wrap. The menuki（目貫）, made of blackened white copper（煮黒白銅）, are shaped as sword-dragons（剣龍）. The fuchi and kashira（縁頭）, made from blackened white copper, are engraved with wave-dragon（波龍）motifs. The tsuba（鍔）is a Maru-gata（丸形）design forged from white copper（白銅）with a blackened finish（煮黒仕上げ）. The surface shows dragons, clouds, waves, and rocks（雲・龍・波・岩）.

TangGu (湯谷) Kobuse Blade

This blade is hand-forged (Tezukuri / 手作り) using our own refined steel, following the principles of Japanese swordsmithing. It features a Kobuse-zukuri (甲伏造) laminated construction, reflecting the structure of traditional Tamahagane (玉钢) swords.

Blade Forging Details

• Blade Name: TangGu Traditionally Forged Kobuse Blade (甲伏造)
  

• Forging Method: This blade is forged in the Kobuse-zukuri（甲伏造） style, where a hardened outer layer of steel is forge-welded over a softer inner core. It is differentially hardened using traditional clay tempering（覆土焼入れ）, resulting in a sharp edge, resilient spine, and a visible hamon（刃文） that reflects both performance and craftsmanship.

• Materials: Steel 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. 32 mm
• Thickness at Base (Motokasane 元重): Approx. 6 mm
• Width at Tip (Sakihaba 先幅): Approx. 24 mm
• Thickness at Tip (Sakikasane先重): Approx. 4 mm
• Kissaki Length (Tip 切先長): Approx. 35 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): The forging pattern shows Masame-hada with Mokume influence（柾目肌交杢目肌）, where masame-hada（柾目肌） fine straight grain lines run longitudinally along the blade, and mokume-hada（杢目肌） swirling woodgrain-like patterns appear in layers. This is achieved through folding and directional forging in the orikaeshi-tanren（折返し鍛錬） process.
• Hamono (Blade Pattern 刃文): The blade has a Gunome-midare（互の目乱れ刃文） temper line, with alternating rounded peaks and valleys formed through clay tempering（覆土焼入れ / Fukutsuchi Yakiire）. Clay is applied to specific areas of the blade before quenching to control the hardness gradient and produce this pattern.

Special Features and Workmanship

Hi (Groove) Engraving

• Type: Marudome-Hi (丸止樋), deeply engraved
• Processing Range: Extends to the tip, fully polished inside the groove

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 surface shows Masame-hada and Mokume-hada（柾目肌交杢目肌）, combining straight grain lines and swirling woodgrain patterns. A Gunome-midare hamon（互の目乱れ刃文） with alternating peaks and curves is formed through clay tempering（覆土焼入れ / Fukutsuchi Yakiire）. The ridge line (Hōmi 峰) is defined through traditional polishing.
    

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Maru-gata tsuba（丸形）, crafted from white copper（白銅）with blackened patina（煮黒仕上げ / Nibu-iro). The surface shows clouds, dragons, waves, and rocks（雲・龍・波・岩）.
• Fuchi-Kashira (縁頭): Blackened white copper（煮黒仕上げの白銅）with engraved wave-dragon motif（波龍図案）on both fuchi（縁）and kashira（頭）.
• Menuki (目貫): Blackened white copper（煮黒白銅）menuki shaped as sword-dragons（剣龍）, placed under the tsuka wrap.
• Habaki (鎺): Polished copper（磨き仕上げの銅 / Migaki dō）habaki（鎺）with rounded lines.
• Samegawa (Ray Skin 柄鮫): Hon-samegawa（本鮫皮 / genuine ray skin）with kofū shiage（古風仕上げ / antique finish).
• Handle Wrapping (Tsuka-maki 柄巻): Green cotton ito（緑色の木綿糸）in hineri-maki（捻巻）style with hishigami（菱紙）forming diamond patterns.

Saya and Accessories

• Saya (Scabbard 鞘): The saya is made in uchigatana koshirae style（打刀拵）with buffalo horn fittings（牛角 / Gyu-kaku）at the koiguchi（口金）, kurigata（栗形）, and kojiri（鞘尻）.
• Saya Lacquer (鞘塗): Finished with dripping gold-style lacquer（滴金塗り）.
• Sageo (Cord 下緒): Green cotton sageo（緑色の木綿下緒 / Midori no momen sageo）tied at the kurigata.

Measurements

• Blade Weight: Approx. 0.6 kg
• Sword Weight (without Saya): Approx. 0.95 kg
• Total Weight: Approx. 1.2 kg
• Overall Length: Approx. 102 mm