History of Hemmi Slide Rules in Japan

(Written in early 2010; lasted updated on July 28, 2024)

The following brief timelime-format history was basically taken from a large general catalog published by Hemmi Slide Rule in 1960.

1894

It is believed that the slide rule first came to Japan when Dr. Ritaro Hirota and Toragoro Kondo, the latter as the Head of the Construction Section of the Internal Affairs Ministry, visit the US and Europe, and bring a Mannheim slide rule back with them from France.

1895

Hemmi Jiro, was working as a scale divider at the time, began research into manufacturing slide rules, this representing the beginnings of slide rule manufacturing in Japan.

1912

The basis for founding Hemmi Slide Rule was established. As a result of a study made of materials, bamboo indigenous to Asia, was selected as the material, resulting in the granting of patents for a bamboo slide rule not only in Japan, but in England and France in 1920, and in the US, China, and Canada in 1920.

1917

In December, the SUN mark is established as the Hemmi trademark. Being the symbol of Japan itself, the image of the rising sun was thought to bode well for the future of the firm's business.

1923

Hemmi Jiro proposed a unique mechanical cutting method that enabled the achievement of excellent scale accuracy, and succeeded in mass production with uniform quality, this achievement winning wide acclaim.

1925

Hisashi Ohkura, later to be president of Hemmi, joined the management team and succeeded in actively promoting export sales.

1928

In April, the joint capital company Hemmi Seisakusho is established.

1929

The invention of the non-logarithmic P and Q scales by Drs. Sadatoshi Betsumiya and Jisuke Miyazaki was applied to the Japan's first duplex slide rule, which was sold under the model name of Universal, this product winning wide acclaim.

1933

In July, Hemmi Seisakusho was reorganized as a stock company, with a capital of 300,000 yen.

1935

Director Shinzaburo Ohno was sent to the US and Canada to develop marketing channels overseas. In December, capital was increased to 500,000 yen, this to be increased further to 750,000 yen in 1940.

1938

One-time research department head Eimei Hirano proposed the trig function SI and TI scales.

1940

The main production facility was constructed in Shirako in Saitama Prefecture, hereafter to be called the Shirako Factory, on a plot of approximately 40,000 square meters (approximately 425,000 square feet). Hemmi Jiro was honored by receipt of a government award on the occasion of the 2600th anniversary of the legendary ascension of the Emperor Jimmu to the throne.

1943

Hemmi Seisakusho constructs its Matsuyama Factory. Slide rules are used in Japanese middle school textbooks for the first time.

1945

The Chichibu Factory is constructed, and production levels increase sharply.

1946

The company name is changed to Hemmi Keisanjaku KK (Hemmi Slide Rule).

1950-51

The Versalog slide rule is jointly developed with the Frederick Post company in the US. Standard duplex slide rules are redesigned as the new models 250, 255, 256, and 259, aimed at the US market. The slide rule is again made a compulsory part of the curriculum in middle schools.

1952

Hemmi Jiro is honored by receiving a government award.

The first edition of Keisanjaku Report (Slide Rule Report) is issued as the official publication of Hemmi Slide Rule. In August, the manager of the Shirako Factory is sent to the US to interact closely with Frederick Post, the Hemmi representative, in research.

In November, the Tokyo Chamber of Commerce holds the first Slide Rule Competition, an event which is to be held once each year.

1953

Hemmi Jiro dies, and is posthumously presented by the government with an award for his achievements.

1954

In August, the president of Richardson & Company, the Hemmi Hong Kong representative visited Japan to discuss expanding the business.

In October, Alfred F. Kunz of Siber Hegner Co., Ltd., Zurich, the Hemmi representative in Switzerland visits Japan to discuss, among other things, methods of promoting the slide rule.

The Japan Chamber of Commerce establishes the Slide Rule Skill Certification Examination system, the first examination being held in November. The Chamber, with the backing of the Ministry of Education, holds its first open paper contest, inviting papers from middle school teachers on the theme of their methods of teaching the use of the slide rule.

Director Ohkura becomes a managing director.

1955

Director Norio Matsumoto becomes the head of the Shirako Factory. Improvements are made in both quality and production levels. A proposed new two-story factory building, with environmental control (reinforced concrete construction) is built (approximately 1400 square meters (15,000 square feet)).

In November, R. J. Piehl, president of Frederick Post Co., visits Japan to discuss a plan for expanded business.

1956

The 60th anniversary of founding is held, with awards given to personnel who had made contributions related to the slide rule. Developmental History of the Slide Rule is published to mark this event.

The Kinki District Slide Rule Education Association is formed by a large number of teachers directly involved in teaching.

The sales department is moved to Konnocho in Tokyo's Shibuya Ward, and capital is increased to 75 million yen.

In May, O. M. De Leon, the president of Hemmi's representative (De Leon Import & Export Co., Manila) in the Phillipines, visits Japan for the third time.

In July, A. Richardson (Mr. K. M. (Aub) Richardson), sales manager of Hemmi's Australian representative, E. Esdaile & Sons Pty Ltd., Sydney, visits Japan to discuss the Australian market.

1957

Seiichi Matsunaga, director and head of sales, visits the US and Canada on a fact-finding mission.

With the backing of the Ministry of Education and the Japan Association for Mathematics Education, the second open paper contest, inviting papers from teachers on the theme of their methods of teaching how to establish the decimal point position.

The Kyushu Area Slide Rule Education Association is established, followed by founding of the Tokyo Slide Rule Education Association and the Shikoku Slide Rule Education Association. All of these organizations issued a publication called Slide Rule Education.

1958

In January, the First Japanese Slide Rule Skill Certification Examination is held, with the backing of the Japan Chamber of Commerce and Hemmi Slide Rule, this resulting in a sharp increase in public awareness of the slide rule.

In March, C. H. Rayner, president of Berrick Brothers Ltd., London, the English representative of Hemmi visits Japan to discuss advertising and the prospects for the future.

In July, Mrs. E A. Esdaile of Hemmi's Australian representative, E. Esdaile & Sons Pty Ltd., Sydney, visits Japan for talks about expanding the business in that market.

In October, the firm introduces the newly designed Model 2664S 10-inch slide rule, targeted for use in slide rule competitions and certification examinations. This slide rule uses a light green scale, a first in Japanese slide rules.

1959

In January, the Model P23 (7-inch) slide rule, a new style of slide rule for student use, is introduced, using plastic as a material for the first time.

The January 18th issue of the weekly Yomiuri Shukan recommends bamboo slide rules made by Hemmi, classed as a top Japanese manufacturer, in a two-page article which describes the Shirako Factory.

Hemmi Jiro

Hemmi Slide Rules bears the name of its founder, Jiro Hemmi and continues to operate, albeit producing items totally unrelated to slide rules.

There is some variation in the way Hemmi's family name is Romanized, with very early occurences sometimes being spelled Henmi, including markings on slide rules.

1878: Born 6 November.
1890: Graduated primary school in Chiba Prefecture.
1893: Joined Nakamura Surveying Instruments in July as a reduction scale worker.
1899: Struck out on his own in March to manage a business making slide rules.
1941: Retired from Hemmi Slide Rule for health reasons.
1953: Died 4 April.