Katana Radiant Warrior Maru Blade Kōbu Koshirae 光武

Clay Tempered Full Tang Shinken (真剣) | Radiant Warrior Katana: TangGu (湯谷) Maru Blade (丸造) + TangGu (湯谷) Kōbu Koshirae (光武拵)

This katana is hand-forged (Tezukuri / 手作り) from high-carbon modern steel (高炭素現代鋼) in the Maru-zukuri (丸造) style. The blade is clay-tempered (yaki-ire / 焼入れ) to produce a gonome hamon (互の目刃文). The koshirae includes a maru-gata tsuba (丸形鍔) made of tetsu (鉄地, iron) with a blackened finish (煮黒) and a spoke-style openwork design (透かし輪文). The fuchi-kashira (縁頭) are made of hakudo (白銅), blackened (煮黒), and engraved with karakusa motifs (唐草文). The habaki (鎺) is made of suaka (素赤銅). The menuki (目貫) are made of hakudo (白銅), blackened (煮黒), and shaped in warrior designs (武者図). The tsuka is wrapped in light yellow synthetic fiber ito (浅黄色合成柄糸) over natural samegawa (鮫皮) with hishigami (菱紙) forming a diamond pattern (菱組). The saya is finished in black glossy lacquer (黒色光沢塗). The sageo (下緒) is light yellow synthetic fiber (浅黄色合成下緒), tightly woven.

TangGu (湯谷) Maru Blade

This blade is hand-forged (Tezukuri / 手作り) from high-carbon modern steel (高炭素現代鋼) in a monosteel construction called Maru-zukuri (丸造).

Blade Forging Details

• Blade Name: TangGu Traditionally Forged Maru Blade (丸造)
• Forging Method: This blade is forged in the Maru-zukuri (丸造) style from a single piece of modern high-carbon steel. It is clay-tempered (yaki-ire / 焼入れ) to produce a hardened edge with a visible hamon (刃文).
• Materials: Modern high-carbon steel (kōtanso gendai-kō / 高炭素現代鋼)
• Purpose: Designed for Iaido (non-sharpened), Kenjutsu, and Tameshigiri (test cutting) practice

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): None (Modern monosteel; no visible hada)
• Hamono (Blade Pattern 刃文): Clay-tempered gonome-style (互の目) hamon – The blade is differentially hardened (yaki-ire / 焼入れ) to produce a temper line.

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:
  • High-grade shaping polish 上・成形研磨
  • High-grade rough polish 上・下研ぎ
  • High-grade final polish 上・仕上げ研磨
• Key Features:
  • Refined blade geometry and balanced weight distribution
  • Exceptional sharpness and durability with a clean, bright-polished edge (Hashiro)
    

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Maru-gata Tsuba (丸形鍔) – Forged from tetsu (鉄地, iron) with a circular spoke-style openwork design (透かし輪文).
• Fuchi-Kashira (縁頭): Made from hakudo (白銅), blackened (煮黒) and engraved with karakusa motifs (唐草文).
• Menuki (目貫): Made from hakudo (白銅), blackened (煮黒) and shaped in warrior designs (武者図).
• Habaki (鎺): Suaka Habaki (素赤鎺) – Made from plain copper (素赤銅).
• Samegawa (Ray Skin 柄鮫): Natural rayskin (鮫皮) beneath the tsuka-maki.
• Handle Wrapping (Tsuka-maki 柄巻): Light yellow synthetic fiber ito wrapped over hishigami (菱紙) in a diamond pattern (菱組).

Saya and Accessories

• Saya (Scabbard 鞘): Traditional-style saya (拵風鞘), reinforced with water buffalo horn (牛角) at the koiguchi (鞘口), kojiri (鐺), and kurigata (栗形) for added durability.
• Saya Lacquer (鞘塗): Black glossy lacquer (黒色光沢塗).
• Sageo (Cord 下緒): Light yellow synthetic fiber sageo (浅黄色合成下緒), tightly woven.

Measurements

• Blade Weight: Approx. 0.65 kg
• Sword Weight (without Saya): Approx. 1.0 kg
• Total Weight: Approx. 1.3 kg
• Overall Length: Approx. 102 mm