KOA ISSHIN MANTETSU
There has been considerable speculation as to who made and what
"Koa Isshin Mantetsu" and "Mantetsu" signed blades represent.
Fuller and Gregory in their book "A Guide to Showa Swordsmiths", speculate whether
this was the name of a swordsmith or possibly a patriotic phrase. "Koa Isshin" can be
translated as "Asia-one heart" - a good patriotic slogan for Japan during WW II.
It may also be referring to the "Greater East Asia Co-Prosperity Sphere", Japan's version
of the Monroe doctrine, which began in 1932 with Japan's occupation of Manchuria.
The mei at left translates as "Koa Isshin Mantetsu saku". The mei at right
translates "Mantetsu Kitae Tsukuru Kore". These blades normally used
the Japanese zodiacal dating method.
The Hawley reference number for Koa Isshin blades is ISH-1. For other examples of
Koa Isshin mei including a rare early example, see the Showa Oshigata Database.
According to the Nihon To Daihyakka Jieten by Dr. Fukunaga,
mantetsu steel was developed at the Dairen Manchurian Railroad Factory beginning in
September of 1937, and was made specifically for the production of sword blades. They were
successful in making steel that was close to pure iron. A sword factory was established and
production begun in November of 1937. The swords were signed
"Mantetsu Kitau Tsukuru Kore".(2) The "Koa Isshin" patriotic phrase was used beginning in 1939.(4)
According to the book, "Koa Isshin", that The South Manchuria Railway Company (Mantetsu) published in 1939
the manufacturing method of the blade was termed "Moro-Zutsumi". According to the "Dai Nippon Token Shoko Meikan" (pub 1942), Mr.Suzuki Kohdo who was a non-regular employee staff of Mantetsu invented a special process of manufacture of the Koa-Isshin sword. According to this book in 1939 the factory manufactured 400 Koa-Isshin swords a month.
Two swordsmiths were invited to the Mantetsu facility to teach sword making; they were
Takeshima Hisakatsu and Wakabayashi Shigetsugu. Shigetsugu came back to Japan before the end of the war
and became Rikugun Jumyo Tosho. (5)
Cross sections of Koa Isshin blades as published in "Koa Isshin".
The composition of the blade's skin steel (kawagane) was Carbon: 0.57%, Manganese: 0.05%,
Sillicon: 0.17%, Phosphrus: 0.018%, Sulfur: 0.003%
The composition of the blade's core steel (shingane): Carbon: 0.23%, Manganese: 0.15%m Sillicon: 0.21%, Phosphrus: 0.020%, Sulfur: 0.008%. (5)
Blades signed "Koa Isshin" tend to be well finished with good attention
paid to the carving of the mei and finish of the nakago. The hada is usually described as ko-itame or nashiji and the hamon is normally done in suguha. All that I have encountered are in good quality standard Shin-gunto mounts.
A Koa Isshin Mantetsu sword was surrendered by Major General Tamoto on September 20, 1945 to Lt. Col. A.K. Crookshank at
Bentong, Malaya. This sword is currently in the National Army Museum, London England.
In 1944 the Imperial Army sponsored a Shinsaku To Exhibition (newly made sword exhibition)
on the grounds of the Yasukuni Jinja. The exhibition had many sections; blades, gunto,
polishing, etc. One section was for "Koa Isshin" blades. These
blades were made by different smiths and entered in the "Koa Isshin"
section of the exhibition. Thus, it can be concluded that these blades were made by a variety
of swordsmiths as a patriotic gesture for this exhibition. (1)
There are many blades with "mantetsu" in the signature. Normally "mantetsu"
means that the sword was made using Manchurian steel. In the case of Koa Isshin blades,
some scholars feel that the "mantetsu" should be taken very liberally to mean "foreign steel", not just
Manchurian steel. ONLY those blades signed "Koa Isshin Mantetsu" were part of
the Yasukuni Shrine sword exhibition. So far as is known, the exhibition with Koa Isshin blades was held only in 1944. Many swordsmiths were involved in the production of Mantetsu blades and used the "Koa Isshin Mantetsu" mei, hence it is important to judge each blade on its individual merits, not just on its signature.
In their later book, Japanese Military and Civil Swords and Dirks, Fuller and Gregory state
that the Koa Isshin signatures represent better quality laminated, tempered blades which were actually made in Japan from
imported steel while the plain mantetsu signature blades were made in China of bar stock which was oil tempered. (This would
seem to be at odds with the statement above by Dr. Fukunaga.)
Some of the mantetsu blades made in the Dairen Railroad factory may bear the stamp of the
Manchuria Railroad company (right). These were made in the late 1930's and are considered
Other blades with the plain mantetsu mei will have the stamp of the Manchurian
Mukden arsenal, sometimes referred to as the "nan" stamp. This was used from the late 1930's until 1945.
Even though Koa Isshin blades were apparently laminated and tempered, they are not considered
traditionally made; i.e., not true gendaito. Rather they fall into the catagory of blades made by or
using non-traditional methods or materials as was common during the WW II period.
Manchurian steel was highly prized by the Japanese swordsmiths as evidenced by the following article.
Japanese-American Courier, Seattle, Washington, June 4, 1938
[Note: This article first appeared in Japan Times.]
TOKIO -- Swords are still a prime necessity in war time, despite airplanes, armored tanks,
machine guns and repeating rifles. It has been found, and the government has taken special steps,
to see that officers have blades which will suit their needs.
However, the blades they carry these days are not up to the standards of olden times, according
to Hikosaburo Kurihara (see note), expert swordsmith, who recently returned from the Shanghai area,
where with a party of smiths he has repaired 15,000 swords for Japanese officers.
So great was the need found for this repair work that the master smith has gone to the North
China area, where he will attend to the needs of the officers there.
Manchurian steel has been found the best material for blades as proved by experience of officers
in the Shanghai district, the expert said, and he recommended to the War Ministry that metal of
that kind be used in future whenever found available.
"We mended about 15,000 swords in Shanghai," the swordsmith said at his home in Hikawacho,
Akasaka-ku. "Blades of good steel do not snap easily, as did some of those we found. I
recommended to the War Ministry that they make available Manchurian steel to all the
swordsmiths in the country. It is about as strong as any we know of."
"An officer with a damaged sword, and who expects a battle next day is a pitiful sight. I saw
many of them working late at night on their weapons, which may mean life or death to them." (3)
[NOTE: Hikosaburo Kurihara was also known as Kurihara Akihide, the founder of the Nihonto Tanren Denshujo
(Japanese Sword Forging Institute).]
An excellent explanation of Koa Isshin Mantetsu swords can be read at this site:
Thanks to Chris Bowen (1), Harry Watson (2), Joe Svinth (3), Nathan Scott (3),
Ron Hartmann, John Slough (4) ,
Kiyoshi Morita (5) and all who have contributed to the knowledge of Koa Isshin Mantetsu swords.