Katana Vermilion Grass Maru Blade Bokuka Koshirae 朱草

Clay Tempered Full Tang Shinken (真剣) | Vermilion Grass Katana: TangGu (湯谷) Maru Blade (丸造) + TangGu (湯谷) Bokuka Koshirae (墨霞拵)

The uchigatana-style koshirae (打刀拵) combines traditional design with practical function. The blade is forged in Maru-zukuri (丸造) style from proprietary high-carbon steel, a monosteel construction for consistent strength and edge retention. The blade has no visible hada (鍛肌なし). A Suguha with slight Midare（小乱れ交じり直刃）hamon is created through clay tempering (覆土焼入れ). The saya (鞘) is finished in palm bark-style lacquer (棕櫚塗) with a fibrous texture. Koiguchi and kurigata are polished buffalo horn; kojiri is metal reinforced. A black cotton sageo (下緒), tightly woven, completes the scabbard. The tsuka (柄) is wrapped in black cotton ito over aged yellow-toned samegawa (鮫皮), reinforced with hishigami (菱紙). Brass menuki shaped like leaf blades. Fuchi and kashira (縁頭) are brass with karakusa (唐草) patterns. The tsuba (鍔) is a mokko-gata (木瓜形) iron guard with blackened patina (煮黒仕上げ) and plum blossom-shaped sukashi (梅花透かし).

TangGu (湯谷) Maru Blade

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

Blade Forging Details

• Blade Name: TangGu Traditionally Forged Maru Blade (丸造)
• Forging Method: Maru-zukuri（丸造）style with a single piece of high-carbon steel. Clay tempering (覆土焼入れ) creates a hardened edge, softer spine, and visible hamon.
• Materials: Proprietary high-carbon steel（自家製高炭素鋼）refined for hardness, toughness, and grain control.
• 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. 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. 33 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 (鍛肌なし) — forged from monosteel with uniform grain.
• Hamono (Blade Pattern 刃文): Suguha with slight Midare（小乱れ交じり直刃）— formed by clay tempering (覆土焼入れ), mostly straight with subtle undulations.

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 in Maru-zukuri（丸造）style from a single piece of proprietary high-carbon steel. Clay tempering（覆土焼入れ）produces a Suguha with slight Midare（小乱れ交じり直刃）hamon with a brightened edge (Hashiro / 刃白).

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Mokko-gata（木瓜鍔）iron tsuba with blackened patina (煮黒仕上げ), featuring plum blossom-shaped sukashi cutouts.
• Fuchi-Kashira (縁頭): Brass with engraved karakusa（唐草）patterns.
• Menuki (目貫): Brass menuki shaped as leaf blades.
• Habaki (鎺): Hand-forged brass with antique finish.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin aged to a soft yellow hue.
• Handle Wrapping (Tsuka-maki 柄巻): Black cotton ito, hineri-maki wrapping style.

Saya and Accessories

• Saya (Scabbard 鞘): Katana-style (打刀拵) scabbard with buffalo horn koiguchi and kurigata. Kojiri reinforced with metal for durability.
• Saya Lacquer (鞘塗): Palm bark-style lacquer (棕櫚塗) with natural textured surface and earthy tones.
• Sageo (Cord 下緒): Black cotton sageo, 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. 100 mm