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astronomy

Shibukawa Shunkai

Shibukawa Shunkai is a astronomy 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 Shibukawa Shunkai rather than just read about it. In short: Shibukawa Shunkai or Shibukawa Harumi (渋川 春海; December 27, 1639 – November 1, 1715) born as Yasui Santetsu (安井 算哲), later called Motoi Santetsu (保井 算晢), was a Japanese scholar, go player and the first official astronomer appointed of the Edo period. He revised the Chinese lunisolar calendar at the shogunate request, drawing up the Jōkyō calendar which was issued in 1684 during the Jōkyō era.

Shibukawa Shunkai — main illustration
Shibukawa Shunkai — illustration

Key takeaways

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

Reference excerpt

Shibukawa Shunkai or Shibukawa Harumi (渋川 春海; December 27, 1639 – November 1, 1715) born as Yasui Santetsu (安井 算哲), later called Motoi Santetsu (保井 算晢), was a Japanese scholar, go player and the first official astronomer appointed of the Edo period. He revised the Chinese lunisolar calendar at the shogunate request, drawing up the Jōkyō calendar which was issued in 1684 during the Jōkyō era. In 1702, he changed his name to Shibukawa Sukezaemon Shunkai and retired by 1711. As a go player, he was affiliated with the Yasui house, calling himself initially (after his father) Yasui Santetsu II. He is mentioned as a Tengen player in Yamashita Keigo's book: Challenging Tengen. Shibukawa Shunkai (as Yasui Santetsu) is the central character in the 2012 film Tenchi: The Samurai Astronomer by Yōjirō Takita.

Notes

Illustrations

Shibukawa Shunkai: Shibukawa Shunkai
Shibukawa Shunkai
Shibukawa Shunkai: Jōkyō calendar published in 1729. Exhibit in the National Museum of Nature and Science, Tokyo, Japan.
Jōkyō calendar published in 1729. Exhibit in the National Museum of Nature and Science, Tokyo, Japan.
Shibukawa Shunkai: "Tenmon Bunya no Zu", written by Shibukawa Shunkai in 1677. "Tenmon Bunya no Zu" means star chart.
"Tenmon Bunya no Zu", written by Shibukawa Shunkai in 1677. "Tenmon Bunya no Zu" means star chart.
Shibukawa Shunkai: Papier-mache globe created by Shibukawa Shunkai in 1695. One of the Important Cultural Properties of Japan. Exhibit in the National Museum of Nature and Science, Tokyo, Japan.[1]
Papier-mache globe created by Shibukawa Shunkai in 1695. One of the Important Cultural Properties of Japan. Exhibit in the National Museum of Nature and Science, Tokyo, Japan.[1]
Shibukawa Shunkai: Shunkai's grave at Tokyo
Shunkai's grave at Tokyo

Worked examples

Example 1 — a first encounter with Shibukawa Shunkai

Start with the simplest possible case. Write down what Shibukawa Shunkai claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, 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 Shibukawa Shunkai 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 Shibukawa Shunkai 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 Shibukawa Shunkai

In research
Shibukawa Shunkai appears in astronomy 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 Shibukawa Shunkai 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
Shibukawa Shunkai is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1639 births, 1715 deaths, 17th-century Go players, so understanding it makes those chapters shorter.
In everyday life
Look for Shibukawa Shunkai 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 Shibukawa Shunkai in 20 minutes

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

Frequently asked questions

What is Shibukawa Shunkai in simple terms?

Shibukawa Shunkai or Shibukawa Harumi (渋川 春海; December 27, 1639 – November 1, 1715) born as Yasui Santetsu (安井 算哲), later called Motoi Santetsu (保井 算晢), was a Japanese scholar, go player and the first official astronomer appointed of the Edo period. He revised the Chinese lunisolar calendar at the…

Why does Shibukawa Shunkai matter?

Because it connects several astronomy 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 Shibukawa Shunkai?

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 Shibukawa Shunkai.

Tags

  • 1639 births
  • 1715 deaths
  • 17th-century Go players
  • 17th-century Japanese astronomers
  • 18th-century Japanese astronomers
  • Globe makers
  • Japanese Go players
  • Japanese astronomer stubs
  • Science and technology during the Edo period

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