Katana Black Wave Maru Blade Kuronami Koshirae 黒浪

Clay Tempered Full Tang Shinken (真剣) | Black Wave Katana: TangGu (湯谷) Maru Blade (丸造) + TangGu (湯谷) Kuronami Koshirae (黒浪拵)

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) construction style. The blade is clay-tempered (yaki-ire / 焼入れ) to produce a gunome hamon (互の目刃文). The koshirae features a mokko-gata tsuba (木瓜形鍔) forged from tetsu (鉄地, iron) with a blackened finish (煮黒) and an openwork ocean wave motif (透かし波). The fuchi-kashira (縁頭) are made of hakudō (白銅), blackened (煮黒), and engraved with wave motifs (波紋). The habaki (鎺) is made of suaka (素赤銅), while the menuki (目貫) are hakudō (白銅), blackened, and shaped in a wave design (波模様). The tsuka is wrapped in brown ito (茶色柄糸) over natural samegawa (鮫皮) with hishigami (菱紙) forming a precise diamond pattern (菱組). The saya is finished in a glossy black lacquer (黒光沢塗り鞘), providing a smooth and reflective surface. The sageo (下緒) is brown (茶色下緒), tightly woven for durability.

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: 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. 25 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)
• Temper Line (Hamon 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

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Mokko-gata Tsuba (木瓜形鍔) – Forged from tetsu (鉄地, iron) with an openwork ocean wave motif (sukashi nami 透かし波).
• Fuchi-Kashira (縁頭): Made from hakudo (白銅, white copper), blackened (煮黒) and engraved with wave motifs (波紋).
• Menuki (目貫): Made from hakudo (白銅), blackened (煮黒) and shaped in a wave design (波模様).
• Habaki (鎺): Shakudo Habaki (赤銅鎺) – Made from reddish copper alloy (shakudo / 赤銅) with a polished surface.
• Samegawa (Ray Skin 柄鮫): Natural rayskin (samegawa / 鮫皮) beneath the tsuka-maki.
• Handle Wrapping (Tsuka-maki 柄巻): Brown cotton (or rayon) 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): Glossy black lacquer with subtle speckled shimmer effect.
• Sageo (Cord 下緒): Brown rayon 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. 102 mm