Katana Misty Bamboo Sanmai Blade Takegasumi Koshirae 紫箏

Clay Tempered Full Tang Shinken (真剣) | Misty Bamboo Katana: TangGu (湯谷) Sanmai Blade (三枚造) + TangGu (湯谷) Takegasumi Koshirae (竹霞拵)

This katana is forged in sanmai（三枚）construction, with a hardened steel core between softer outer layers. The surface shows masame-hada（柾目肌）grain and a straight suguha（直刃）hamon, formed through clay tempering（覆土焼入れ / Fukutsuchi Yakiire）. The blade is made in shinogi-zukuri（鎬造）style with an iori-mune（庵棟）spine and ō-kissaki（大切先）tip. It weighs approximately 500 grams. The koshirae（拵）features an elliptical copper tsuba（楕円形鍔）with a carved bamboo motif（竹文様）and black patina finish（煮黒 / Nuriguro）. The fuchi and kashira（縁頭）are blackened copper（煮黒銅）with simple lines. Silver bamboo-leaf menuki（目貫）are placed under the wrap. The tsuka（柄）is wrapped in deep blue cotton ito using hishigami（菱紙）over unbleached samegawa（本鮫皮）ray skin in a diamond pattern. The saya（鞘）is hardwood with purple lacquer. The koiguchi（鞘口）, kojiri（鞘尻）, and kurigata（栗形）are reinforced with water buffalo horn（牛角）. A dark purple cotton sageo（下緒）is tied to the kurigata.

TangGu (湯谷) Sanmai Blade

This blade is hand-forged (Tezukuri / 手作り) using our own refined steel in Sanmai-zukuri（三枚造）construction, with a hard edge forge-welded between two softer outer layers.

Blade Forging Details

• Blade Name: TangGu Traditionally Forged Sanmai Blade (三枚造)
• Forging Method: This blade is forged in the Sanmai-zukuri（三枚造）style, with a hard steel core forge-welded between two layers of softer outer steel. It is differentially hardened using clay tempering（覆土焼入れ）, producing a hardened edge and a softer spine. This process also creates a visible hamon（刃文）.
• 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. 25 cm
• Width at Base (Motohaba 元幅): Approx. 30 mm
• Thickness at Base (Motokasane 元重): Approx. 5.5 mm
• Width at Tip (Sakihaba 先幅): Approx. 22 mm
• Thickness at Tip (Sakikasane先重): Approx. 3.5 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-sized tip 大切先)

• Forging Pattern (Hada 鍛肌): Masame-hada（柾目肌）— a straight-grained forging pattern running parallel along the blade, formed through layered forging in sanmai-zukuri（三枚造）construction.
• Hamono (Blade Pattern 刃文): Suguha（直刃）— a straight temper line created through clay tempering（覆土焼入れ / Fukutsuchi Yakiire）.

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:
  • Hand polishing reveals masame-hada（柾目肌）grain along the surface, and a hakuba（刃白）temper line near the edge. The shinogi（鋒身筋）ridge is mirror-polished.

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Dai-enkei（楕円形）tsuba made of copper（銅）, finished with black patina（煮黒 / Nuriguro）. The surface has a carved bamboo motif（竹文様）.
• Fuchi-Kashira (縁頭): Blackened copper（煮黒銅）, matching the tsuba.
• Menuki (目貫): Silver bamboo leaf menuki placed under the tsuka-ito（柄糸）.
• Habaki (鎺): Polished copper（銅）habaki.
• Samegawa (Ray Skin 柄鮫): Unbleached natural ray skin（本鮫皮）under the wrap.
• Handle Wrapping (Tsuka-maki 柄巻): TDeep blue cotton ito wrapped with hishigami（菱紙）in a diamond pattern.

Saya and Accessories

• Saya (Scabbard 鞘): Traditional-style saya (拵風鞘), reinforced with water buffalo horn at the koiguchi (mouth), kojiri (end), and kurigata (cord knob).
• Saya Lacquer (鞘塗): The saya is finished in purple lacquer with a glossy surface.
• Sageo (Cord 下緒): Dark blue cotton sageo tied to the kurigata（栗形）in a traditional style.

Measurements

• Blade Weight: Approx. 0.5 kg
• Sword Weight (without Saya): Approx. 0.80 kg
• Total Weight: Approx. 1.0 kg
• Overall Length: Approx. 102 mm