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TACHI

A tachi (太刀) was a type of traditionally made Japanese sword (nihonto) worn by the samurai class of feudal Japan. The tachi style of swords preceded the development of the katana—the first use of the word katana to indicate a blade different from tachi appears toward the end of the twelfth century.
An authentic tachi that was manufactured in the correct time period averaged 70–80 centimeters (27 9/16 - 31 1/2 inches) in cutting edge length (nagasa) and compared to a katana was generally lighter in weight in proportion to its length, had a greater taper from hilt to point, was more curved with a smaller point area.
Unlike the traditional manner of wearing the katana, the tachi was worn hung from the belt with the cutting-edge down, and was most effective when used by cavalry. Deviations from the average length of tachi have the prefixes ko- for "short" and ō- for "great, large" attached. For instance, tachi that were shōtō and closer in size to a wakizashi were called kodachi. The longest tachi (considered a 15th-century ōdachi) in existence is more than 3.7 metres (12 ft) in total length with a 2.2 metres (7 ft 3 in) blade, but believed to be ceremonial.
For a sword to be worn in "tachi style" it needed to be mounted in a tachi koshirae. The tachi koshirae had two hangers (ashi) which allowed the sword to be worn in a horizontal position with the cutting edge down.

GENERAL DATA
OVERALL LENGTH: 103 cm / 40.6 inch	BLADE LENGTH: 70 cm / 27.6 inch
TSUKA LENGTH: 26 cm / 10.24 inch	BLADE WIDTH: 3.2 cm / 1.26 inch
BLADE THICKNESS: 0.7 cm / 0.28 inch	BLADE HRC: 60
BLADE CRAFT
BLADE CRAFT: fully hand folded forged by 15 times (32786 layers), hand polished, clay hardened, water quenching
BLADE MATERIAL: folded 1095 carbon steel + iron core	BLADE SHAPE: shinogidukuri
NAKAGO: full tang	BLADE CONSTRUCTION: kobuse
HAMON: real hamon, clay hardened line	BO-hi: no
SHARPNESS: ★★★★★	MIRROR EFFECT: ★★★★★
MOUNTINGS
TSUKA(HANDLE): hard wood core, hineri maki	MEKUGI: 2 bamboo pegs
TSUKA-ITO: black synthetic silk cord	SAMEGAWA: genuine white rayskin
FUCHI / KASHIRA: golden peony pattern, brass	MENUKI: brass
TSUBA(HAND GUARD): gold-plated brass	SEPPA: high quality red copper
HABAKi: brass
SAYA: specialized tachi saya with high quality lion pattern fittings, black synthetic silk sageo
PACKAGE
1 sword with saya	1 black cotton bag
NOTICE
Sword display holder(stand) is not included	Manual measurement error range 1-2 cm

The kobuse is constructed of two different kinds of steel, the core steel and the outer steel, where the core steel is wrapped with the outer steel.
As to the tempering, the outer steel is more sensitive than the core steel. In this case the outer steel is harder than the core steel.

Folded Steel

This means that the carbon steel is folded by 11 times to produce 2048 layers. The higher quantity of layers provides more unique and mystical hada patterns, which defines and displays the craftsman’s experience and knowledge of traditional metallurgy passed down from generation to generation. Only the utmost skilled bladesmiths (Toushyo) and polishers (Togi-shi) can bring out the beauty and life from the Shinsakuto live blade. During the forging process, all of the slags and impurities of the steel are burned off and folded forged to an uncompromised strength with an sharp cutting edge. The final carbon content is 1% and the hardness is an impressive HRC 55°on the Rockwell Scale. This high quality blade can easily cut through tatami straw mats or bamboo for Tameshigiri or Batto-do use.

Clay Hardening

Before being quenched, a special clay mixture can be applied onto the blade to harden the edge and obtain different hardness on the blade. The clay mixture was a special recipe and considered a crucial trade secret, guarded protectively by sword making masters. It would contain such things as feathers, powdered bones, grass, etc. and would be applied to the edge of the blade before being quenched. During quenching, a chemical reaction between the clay mixture and the hot steel occurs during the sudden temperature drop and carbon is fed into the blade in high amounts, creating an extremely tough edge. A clay hardened blade can only be quenched in water, thus increasing the defect rate even more.

Another way for clay tempering is to apply clay along the blade but let edge exposed. Thus, while quenching the blade into water,the uncovered edge will cool down suddenly, but the rest of blade will cool down slowly. Such differential temperature change results in the different hardness of the blade. So the edge is tough enough to cut, where the back of blade is soft /flexible enough to absorb the impact during cutting. Such quenching process usually will leave beautiful wavy tempered line on the blade, as known as "hamon" in Japanese swords term.