Katana Tiger Moon Sanmai Blade Kokusei Koshirae 寅月

Clay Tempered Full Tang Shinken (真剣) | Tiger Moon Katana: TangGu (湯谷) Sanmai Blade (三枚造) + TangGu (湯谷) Kokusei Koshirae (黒星拵)

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 the edge has 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）geometry with an iori-mune（庵棟）spine and ō-kissaki（大切先）tip. It weighs approximately 500 grams. The koshirae（拵）features a round copper tsuba（丸形鍔）with a carved tiger and rabbit motif（虎兔図）, finished with black patina（煮黒 / Nuriguro）. The fuchi and kashira（縁頭）are blackened copper（煮黒銅）with simple contours. The tsuka（柄）is wrapped in brown cotton ito using hishigami（菱紙）over unbleached samegawa（本鮫皮）ray skin. Silver menuki（目貫）are placed under the wrap. The saya（鞘）is hardwood with black gloss lacquer and reflective particles. The koiguchi（鞘口）, kojiri（鞘尻）, and kurigata（栗形）are reinforced with water buffalo horn（牛角）. A brown 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:
  • The surface shows masame-hada（柾目肌）with straight grain lines. A hakuba（刃白）temper line runs along the edge, formed through clay tempering（覆土焼入れ / Fukutsuchi Yakiire）. The shinogi（鋒身筋）ridge is mirror polished.

Fittings and Mountings

Blade Fittings

• Tsuba (Handguard 鍔): Maru-gata（丸形）tsuba made of copper（銅）, finished with black patina（煮黒 / Nuriguro）. The surface has a carved tiger and rabbit motif（虎兔図）.
• Fuchi-Kashira (縁頭): Copper（銅）with black patina（煮黒 / Nuriguro）, matching the tsuba.
• Menuki (目貫): The menuki placed under the brown tsuka-ito（柄糸）.
• Habaki (鎺): Shakudō（赤銅 / purple copper）habaki, polished.
• Samegawa (Ray Skin 柄鮫): Natural unbleached ray skin（本鮫皮）under the wrap.
• Handle Wrapping (Tsuka-maki 柄巻): Brown cotton ito wrapped with hishigami（菱紙）in 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): Black gloss lacquer with reflective particles.
• Sageo (Cord 下緒):Brown 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