engineering

Ryōichi Yazu

Ryōichi Yazu is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ryōichi Yazu rather than just read about it. In short: Ryōichi Yazu (矢頭良一, Yazu Ryōichi; 30 June 1878 – 16 October 1908) was a Japanese inventor. He is best known for his invention of Japan's first mechanical calculator.

Key takeaways

Ryōichi Yazu belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ryōichi Yazu to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ryōichi Yazu from memory before moving on to harder problems.

Reference excerpt

Ryōichi Yazu (矢頭良一, Yazu Ryōichi; 30 June 1878 – 16 October 1908) was a Japanese inventor. He is best known for his invention of Japan's first mechanical calculator.

Birth and education Ryōichi Yazu was born in Buzen, Fukuoka 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.

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 (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 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).

See also Earliest calculators Chūhachi Ninomiya

Notes

References Yamada, Akihiko (March 2006). "Biquinary Mechanical Calculating Machine, "Jido-Soroban" (automatic abacus), built by Ryoichi Yazu" (PDF). Survey Reports on the Systemization of Technologies. 5. National Science Museum of Japan. Archived (PDF) from the original on 2011-03-02. Yamada, Akihiko (2010). "The First Japanese Mechanical Calculating Machine "Jido Soroban"(Automatic Abacus) Developed in Meiji Era". IEICE ESS Fundamentals Review (in Japanese). 4 (2): 105–112. Bibcode:2010ESSFR...4..105Y. doi:10.1587/essfr.4.105. Archived from the original on 2018-01-30.

External links Mechanical Calculating Machine (Automatic Abacus) Description of the calculator in the Computer Museum of the Information Processing Society of Japan.

Illustrations

Ryōichi Yazu: Ryōichi Yazu and his Patent Yazu Arithmometer. — Ryōichi Yazu and his Patent Yazu Arithmometer.

Worked examples

Example 1 — a first encounter with Ryōichi Yazu

Start with the simplest possible case. Write down what Ryōichi Yazu claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ryōichi Yazu before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ryōichi Yazu ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ryōichi Yazu

In research: Ryōichi Yazu appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ryōichi Yazu in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ryōichi Yazu is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1878 births, 1908 deaths, Aerodynamicists, so understanding it makes those chapters shorter.
In everyday life: Look for Ryōichi Yazu outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ryōichi Yazu in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ryōichi Yazu means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ryōichi Yazu out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ryōichi Yazu in simple terms?

Ryōichi Yazu (矢頭良一, Yazu Ryōichi; 30 June 1878 – 16 October 1908) was a Japanese inventor. He is best known for his invention of Japan's first mechanical calculator.

Why does Ryōichi Yazu matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ryōichi Yazu?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ryōichi Yazu.