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Rikugun Jumei Tosho Manufacturing Specifications

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I received the document cited by Morita san which addresses the manufacturing requirements specified by the army to contract smiths (Jumei Tosho) for making commissioned officer's gunto. Thank you very much Morita san....


I do not have the time to translate this document verbatim as it is written in the older style Japanese which is very difficult for me to read. I have enough trouble with the modern language! I summarized the main points however and share them below.


First, though, let me say that this Jumei Tosho program was launched by the military in Showa 17 as a way to standardize and quality control the gunto made for commissioned officers. Prior to this programs there were all types of swords being made, from fully traditional to western steel/oil quenched Showa-to to mantetsu-to, yasuki-tetsu-to, murata-to, denki-tetsu-to, etc. This was an attempt to organize, standardize, and provide a uniform level of quality. Concepts dear to the hearts of Japanese bureaucrats....



Key Points From the Article "Commissioned Officer's Gunto Manufacturing Specifications"


The blade was to be made with tamahagane and hochogane using charcoal. The smiths were required to use their best skill in forging and hardening the blades such that they would be tough and strong. They should cut well and be especially strong against blows from the side and to the mune. The carbon content of the hagane and shingane was specified to be in the following range: hagane: 0.5-0.7% carbon; shingane: 0.05-0.25% carbon.


The shape and dimensions of all parts of the sword blade were specified and a drawing/blueprint existed (not in the original article) which illustrated these dimensions. The sori, mihaba, size of the kissaki, mei, nakago length, weight, etc. were all specified. The shape of the hamon was left up to the smith but was not suppose to be more than medium width. The nakago was to be properly finished with a mei and date inscribed. The blade was to be flat with moderate hamaguri. Shinogi-zukuri with tori-zori.


Swords were made in three length and weight catagories, all with a nakago of 7 sun in length.


small:2.0〜2.1尺  731.25〜768.75 grams

medium:2.1〜2.2尺  768.75〜806.25 grams 

large:2.2〜2.3尺  806.25〜843.75 grams


Latitude was given as far as the shape and length of the blade but the weight specification was strictly enforced.


When the blades were received by the arsenal, they were tested and visually inspected:


The blades were struck forcefully from the side with an 80 mm steel pipe. They should bent less than 60 degrees and not break. The also tested the cutting ability on two 10 cm diameter bundles of straw and a mild steel plate that was 2mm thick, 1 cm wide. The blade should not show a kirikomi more than 2 cm, and should not have hakobore or bend.


The appearance of the blade was inspected. The blade should, in general, be well balanced with the length, shape, and weight within the tolerances of the regulation. The blade should not have hakobore, kizu in the ji, or breaks in the hamon or other harmful kizu.


A few personal comments:


My understanding was that these tests were done to the two test blades which a smith would submit in application to become a Jumei Tosho. I do not think they tested every blade made afterwards under contract....


The article makes no mention of the star stamp but I have heard from several Jumei Tosho that the star stamp was placed on their blades when they were accepted by the army. All star stamp blades I have seen were made by smiths in the Jumei Tosho program...


Swords made by Jumei Tosho that do not have a star stamp were made for private sale by the smith.


I hope this helps to understand the star stamp and the Jumei Tosho system.


Thank you very much to Morita san for sending the scan of the article.

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Chris, I'm honored to be among the first to say "Thank you" for taking the time to write this up.


The RJT program seems pretty mysterious and this helps shed a bright light on what was happening there.


Perhaps this will some day factor this into the "no stamped tangs" import policy, which I believe currently lumps the Good with the bad and prevents star-stamped from being legally imported into Japan.



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You are most welcome...


I should add that the import shinsa process is extremely location and shinsa team member variable. The shinsa in Tokyo is up to speed on WWII era star stamped blades, at least they were a few years ago when I imported some of them. The shinsa that take place outside of Tokyo are another story. I argued for hours one time with the Ministry of Education rep who has supervising the team in Shizuoka when he told them they couldn't license a blade I was importing because it had a showa date. That, according to him, made it a Showa-to. I had to pull out the import shinsa law text that states that blades are to be judged on workmanship irregardless of time period. That satisfied the judges and while it made him look bad, I really needed to get the blade into Japan and had no choice...He knew nothing about swords and should have been piloting a desk somewhere else....You will run into that often outside of Tokyo...

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Hi all,


Thank you so much Mr.Bowen.

I think that English speaking people have a hard work in an English translation very much because the document of specifications is old Kanji style, old expression of words and literary style like the law book.

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These two books are extremely unusual books even in Japan.


Right book is titled [Gun-To], author Rear Admiral Koizumi Chikashige,who was a proposer of the Kai-gunto mount, and designed Kai-gunto mount by him.

Published in 1938.


Left book is titled [Koa-Isshin] Published by South Manchurian Railway Company in 1939.

The researcher of Koa Isshin sword is must read book.


P/S I'm not book seller,but collecter. :lol:


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Wow, those are really rare! You have an excellent library!


Do you have the books by Naruse? (戦ふ日本刀) ,(随筆 日本刀), (実戦刀譚) They are very interesting...


Also very helpful are the monthly magazines published by Kurihara Akihide, "Nihonto Oyobi Nihon Shumi" (日本刀及日本趣味). They are like a diary of all the events pertaining to nihonto from the mid thirties to the end of the war....I have been collecting these for a long time. I have most of them but the search continues...


One other question Morita san...Have you seen the movie "Nihon-to Monogatari" from 1957? Tsukamoto Okimasa is in the movie forging swords....I would love to see this but can't find it anywhere....

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