was a Japanese inventor. He is best known for his invention of Japan's first

mechanical calculator A mechanical calculator, or calculating machine, is a mechanical device used to perform the basic operations of arithmetic automatically, or (historically) a simulation such as an analog computer or a slide rule. Most mechanical calculators we ...

Birth and education

Ryōichi Yazu was born in

Buzen, Fukuoka is a Cities of Japan, city located in Fukuoka Prefecture, Japan. The city was founded on April 10, 1955. As of November 1, 2014, the city has an estimated population of 26,100 and a population density of 235 persons per km². The total area is 11 ...

as the son of a village mayor. He attended primary and middle school in his home village of Iwaya and the city of Buzen. At the age of 16 he left middle school and travelled to Osaka to pursue his interest in flight, studying mathematics and engineering at a private school in Osaka. At the age of 22 he returned to Buzen and began work on a thesis on the mechanics of flight. Two years later he brought the thesis and a model of his calculator on a visit to the novelist and army physician

Mori Ōgai Lieutenant-General , known by his pen name , was a Japanese Army Surgeon general officer, translator, novelist, poet and father of famed author Mari Mori. He obtained his medical license at a very young age and introduced translated German la ...

. Impressed, Ōgai wrote recommendations that led to a special research position at the Tokyo Imperial College of Engineering, where he worked on the design of a propeller-driven airplane.

Mechanical calculator

In March 1902 Yazu applied for a patent on his mechanical calculator, called the Yazu Arithmometer. It was a gear type calculator with a single cylinder and 22 gears, capable of arithmetic calculations up to 16 digits, with automatic carry and end of calculation functions. A special feature was that it accepted input in the biquinary number system familiar to users of the

soroban The is an abacus developed in Japan. It is derived from the ancient Chinese suanpan, imported to Japan in the 14th century. Like the suanpan, the soroban is still used today, despite the proliferation of practical and affordable pocket electr ...

(Japanese abacus). The patent was granted in 1903, and a shop was established to manufacture it. About 200 units were produced and sold, mainly to government agencies, including the Ministry of War, the Home Ministry, the statistics bureau, and agricultural experiment stations, and also to companies such as Nippon Railway. The calculator was expensive, costing 250 yen, more than ten times the monthly salary of a newspaper reporter or lower-level government official. Yazu invested the profits in a factory to build his airplane. But that project was abandoned after his untimely death from

pleurisy Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity ( pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other sy ...

at the age of 31. One of the calculators is preserved in the Kitakyūshū City Museum of Literature. In 2008 the Yazu Arithmometer was listed as item No. 30 in the

Mechanical Engineering Heritage (Japan) The is a list of sites, landmarks, machines, and documents that made significant contributions to the development of mechanical engineering in Japan. Items in the list are certified by the . Overview The ''Mechanical Engineering Heritage'' pro ...

Notes

References

* *

External links

Mechanical Calculating Machine (Automatic Abacus)
Description of the calculator in the Computer Museum of the Information Processing Society of Japan. {{DEFAULTSORT:Yazu, Ryoichi Japanese inventors Japanese aerospace engineers Aviation inventors Aviation pioneers Aerodynamicists 1878 births 1908 deaths People from Buzen, Fukuoka

Birth and education

Mechanical calculator

See also

Notes

References

External links