science

Kodoku

Kodoku 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 Kodoku rather than just read about it. In short: Kodoku (蠱毒, 'curse poison'), also called kodō (蠱道, 'curse method'), kojutsu (蠱術, 'curse technique') and fuko (巫蠱, 'sorcery curse'), is a type of poisonous magic found in Japanese folklore. It is the Japanese derivative of the Chinese gu magic.

Key takeaways

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

Reference excerpt

Kodoku (蠱毒, 'curse poison'), also called kodō (蠱道, 'curse method'), kojutsu (蠱術, 'curse technique') and fuko (巫蠱, 'sorcery curse'), is a type of poisonous magic found in Japanese folklore. It is the Japanese derivative of the Chinese gu magic. It is said to have been widely used in ancient China. It is not clear for how long it has been used, but scholars of Chinese characters such as Shizuka Shirakawa, who advocates the importance of magic in ancient times, have found traces of poison in the oracle bone script of the Yin and Zhou dynasties. The earliest record of worms is in the Geography of the Suishu, which reads:

On May 5th, 100 species of insects were collected, the larger ones were snakes, the smaller ones were lice. Place them inside, let them eat each other, and keep what is left of the last species. If it is a snake, it is a serpent, if it is a louse, it is a louse. Do this and kill a person. To create kodoku, sorcerers would mix several insects in a jar, and let them kill one another until only one survived. The fluids of the insect that survived would be used to poison an individual with a curse that would control them, cause them misfortune, or kill them. The remaining insect could also be used as a sort of "luck charm" granting the one who performed the ritual great wealth. In return the owner is supposed to feed the bug. Neglecting to do so would enrage the insect, if the owner does not equivalently repay the insect by placing all their riches beside a road, plus interest in gold and silver, the insect would devour the home owner. Therefore, this ritual could also be used as a death curse by giving the riches to an ignorant individual. The term kodoku can also be applied to the spirit which is the incarnation of this particular magic (which usually appears in the shape of a worm or other animal). The technique was used in the Nara period.

In fiction

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Kodoku

Start with the simplest possible case. Write down what Kodoku 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 Kodoku 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 Kodoku 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 Kodoku

In research: Kodoku 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 Kodoku 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: Kodoku is common in secondary-school and first-year university syllabi. It links to neighbouring topics History of magic, Insects in religion, Japanese folk religion, so understanding it makes those chapters shorter.
In everyday life: Look for Kodoku 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 Kodoku in 20 minutes

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

Frequently asked questions

What is Kodoku in simple terms?

Why does Kodoku 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 Kodoku?

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 Kodoku.