science

Kōsatsu

Kōsatsu is a science 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 Kōsatsu rather than just read about it. In short: A kōsatsu (Japanese: 高札, literally "High plaque"), also called Seisatsu (Japanese: 制札, literally "Controlling plaque"), was a public notice of the han-lord's or shogun's proclamations earlier in Japanese history. They were local or nationwide laws written on a wooden plate, placed in the kōsatsu-ba of the shukuba or sekisho (関所), the border between han, where there was frequent traffic.

Key takeaways

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

Reference excerpt

A kōsatsu (Japanese: 高札, literally "High plaque"), also called Seisatsu (Japanese: 制札, literally "Controlling plaque"), was a public notice of the han-lord's or shogun's proclamations earlier in Japanese history. They were local or nationwide laws written on a wooden plate, placed in the kōsatsu-ba of the shukuba or sekisho (関所), the border between han, where there was frequent traffic. The kōsatsu was used from the late Nara Period until the early Meiji period. One of the kosatsu in the Edo Period was on prohibiting Christianity. As the people's literacy rate improved and the modern nation emerged, the kōsatsu was abolished in 1873 and eventually replaced by the Kanpō (Japanese government gazette) and other means of public notice.

See also Public notice Kanpō Bulletin board Wall newspaper

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Kōsatsu

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

In research: Kōsatsu appears in science 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 Kōsatsu 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: Kōsatsu is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1873 establishments in Japan, Communications in Japan, History of communication, so understanding it makes those chapters shorter.
In everyday life: Look for Kōsatsu 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 Kōsatsu in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kōsatsu 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 Kōsatsu out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kōsatsu in simple terms?

Why does Kōsatsu matter?

Because it connects several science 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 Kōsatsu?

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 Kōsatsu.