Katana Crimson Wave Sanmai Blade Sekiro Koshirae 赤涛

Clay Tempered Full Tang Shinken (真剣) | Crimson Wave Katana: TangGu (湯谷) Sanmai Blade (三枚造) + TangGu (湯谷) Sekiro Koshirae (赤浪拵)

This katana is forged in sanmai (三枚) construction with a hard core edge and softer outer layers for sharpness and durability. The blade shows masame-hada (柾目肌) grain and a notare-komidare (のたれ小乱れ) hamon, created through clay tempering (覆土焼入れ). It has a shinogi-zukuri (鎬造) shape with an iori-mune (庵棟) spine and ō-kissaki (大切先) tip. The blade weighs about 500 grams, offering balance and agility. The fittings—tsuba (鍔), fuchi, kashira—are solid copper with black patina (煮黒) and wave motifs (波文) in gold and silver. Menuki (目貫) continue the wave theme. The tsuka (柄) is wrapped in dark brown cotton ito over aged white samegawa (鮫皮) with hishigami (菱紙). The saya (鞘) has a high-gloss lacquer finish with buffalo horn reinforcements at the koiguchi. A dark brown cotton sageo (下緒) is tied for secure carrying.

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 pattern produced by layered forging in the sanmai-zukuri style.
• Hamono (Blade Pattern 刃文): Notare-komidare-style hamon（のたれ小乱れ刃文）, formed through clay tempering (覆土焼入れ), with gentle undulations and slight irregularities.

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 sanmai construction provides a hard core edge. The blade weighs approximately 500 grams, offering good handling and agility with solid cutting power. The traditional polish highlights the bright edge (hakuba), matte ji surface (jihada), and a clearly defined, polished shinogi line (hōmi).

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Maru-gata (丸形) handguard made of solid copper (銅 dō) with a black patina (煮黒 nuriguro) finish. Features an openwork wave motif (波文 namimon sukashi) with gold and silver inlays.
• Fuchi-Kashira (縁頭): Black-patinated copper with wave patterns (波文 namimon) and gold-silver inlays.
• Menuki (目貫): Relief-carved wave design placed under the tsuka-ito for grip support and decoration.
• Habaki (鎺): Polished copper (銅) habaki.
• Samegawa (Ray Skin 柄鮫): Genuine ray skin (鮫皮 samegawa) with an aged finish.
• Handle Wrapping (Tsuka-maki 柄巻): Dark brown cotton ito (糸) wrapped using the hishigami (菱紙) method for a secure grip.

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): Crimson-red lacquer with a smooth, reflective finish.
• Sageo (Cord 下緒): Dark brown cotton sageo, securely tied.

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