science

Ken (unit)

Ken (unit) 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 Ken (unit) rather than just read about it. In short: The ken (Japanese: 間) is a traditional Japanese unit of length, equal to six shaku ('Japanese feet'). The exact value has varied over time and location but has generally been a little shorter than 2 meters (6 ft 7 in).

Key takeaways

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

Reference excerpt

The ken (Japanese: 間) is a traditional Japanese unit of length, equal to six shaku ('Japanese feet'). The exact value has varied over time and location but has generally been a little shorter than 2 meters (6 ft 7 in). It is now standardized as 1.82 m. Although mostly supplanted by the metric system, this unit is a common measurement in Japanese architecture, where it is used as a proportion for the intervals between the pillars of traditional-style buildings. In this context, it is commonly translated as "bay". The length also appears in other contexts, such as the standard length of the bō staff in Japanese martial arts and the standard dimensions of the tatami mats. As these are used to cover the floors of most Japanese houses, floor surfaces are still commonly measured not in square meters but in "tatami" which are equivalent to half of a square ken.

Word

Among English loanwords of Japanese origin, both ken and ma are derived from readings of the same character 間. This kanji graphically combines 門 "door" and 日 "sun". The earlier variant character 閒 was written with 月 "moon" rather than "sun", depicting "A 門 door through the crevice of which the 月 moonshine peeps in". The diverse Japanese pronunciations of 間 include on'yomi Sino-Chinese readings (from jian 間 or 间 "room; between; gap; interval") of kan "interval; space; between; among; discord; favorable opportunity" or ken "six feet"; and kun'yomi native Japanese readings of ai "interval; between; medium; crossbred", aida or awai "space; interval; gap; between; among; midway; on the way; distance; time; period; relationship", or ma "space; room; interval; pause; rest (in music); time; a while; leisure; luck; timing; harmony".

History

The ken is based on the Chinese jian. It uses the same Chinese character as the Korean kan. A building's proportions were (and, to a certain extent, still are) measured in ken, as for example in the case of Enryaku-ji's Konponchū-dō (Main Hall), which measures 11×6 bays (37.60 m × 23.92 m), of which 11×4 are dedicated to the worshipers. Inside buildings, available space was often divided in squares measuring one ken across, and each square was then called a ma (間), the term written with the same Chinese character as ken. Traditional buildings usually measure an odd number of bays, for example 3×3 or 5×5. A type of temple's gate called rōmon can have dimensions going from 5×2 bays to the more common 3×2 bays down to even 1×1 bay. The Zen butsuden in the illustration measures 5×5 ken across externally because its 3×3 ken core (moya) is surrounded by a 1-ken aisle called hisashi. The value of a ken could change from building to building, but was usually kept constant within the same structure. There can however be exceptions. Kasuga Taisha's tiny honden's dimensions, for example, are 1×1 in ken, but 1.9×2.6 in meters. In the case of Izumo Taisha's honden, a ken is 6.32 m (20.7 ft), well above its standard value. The distance between pillars was standardized very early and started being used as a unit of measurement. Land area in particular was measured using the ken as a basis. The unit was born out of the necessity to measure land surface to calculate taxes. At the time of Toyotomi Hideyoshi (16th century), the ken was about 1.97 m (6.5 ft), but around 1650 the Tokugawa shogunate reduced it to 1.818 m (5.96 ft) specifically to increase taxes. After the Edo period, the ken started to be called kyōma (京間).

References

Citations

Bibliography Japanese Art Net User System (JAANUS) Dictionary of Japanese Architectural and Art Historical Terminology, articles Kasuga-zukuri, Ken and Kondō. Accessed on May 6, 2009 Iwanami Kōjien (広辞苑) Japanese dictionary, 6th Edition (2008), DVD version

Illustrations

Ken (unit): Japanese ryakuji "abbreviated character" for 間. — Japanese ryakuji "abbreviated character" for 間.

Worked examples

Example 1 — a first encounter with Ken (unit)

Start with the simplest possible case. Write down what Ken (unit) 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 Ken (unit) 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 Ken (unit) 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 Ken (unit)

In research: Ken (unit) 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 Ken (unit) 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: Ken (unit) is common in secondary-school and first-year university syllabi. It links to neighbouring topics East Asian units of measurement, Japanese architectural features, Units of length, so understanding it makes those chapters shorter.
In everyday life: Look for Ken (unit) 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 Ken (unit) in 20 minutes

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

Frequently asked questions

What is Ken (unit) in simple terms?

Why does Ken (unit) 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 Ken (unit)?

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 Ken (unit).