Japanese: Aru, Iru, and Desu




This could be considered the most basic word in the whole language. Technically, such things are known as copulas. Ending a sentence with “desu” affirms the existence of the preceding.

So, if we have:

“Hito desu.” (Hito = a person)

= “That is a person.”


“Kuruma desu.” (Kuruma = car)

= “That is a car.”

Although copulas can be conjugated like verbs, they are in a league all of their own and should be kept separate from “verbs”.


“Desu” is the standard, “polite” form. Speech is usually divided into “polite” and “plain” forms for most verb tenses.

Most standard courses and classrooms teach only the polite versions, because they are considered universally applicable and because “polite” is the classroom standard at any rate. However, to use Japanese in the real world, you really do need to know plain forms.

The plain form for “desu” is “da”. Therefore:

“Hito da.”

“Kuruma da.”

Aside from the tone and implied speaking style, the meaning is absolutely 100% identical.

Past form of “desu” is “deshita”. Past form of “da” is “datta”.

Let’s say a car has been in an accident and is now a piece of scrap.

“Kuruma deshita.” Or, “Kuruma datta.”

It was a car, but is no longer. Poor car.

Aru and Iru

Aru and Iru are fundamental verbs that are considered existence verbs, but that can create mental confusion. More on that in a minute.

The key difference between the two is that aru is for inanimate objects, and iru is for animate objects (i.e. people and animals.)

So naturally, you may wonder, why have existence verbs when you have “desu”? Well, that’s because aru and iru may flag something as existing, but that’s by implication.

What they really indicate is presence.

Example: “Seigi ga koko ni aru!” (正義がここにある!)

“Seigi” is Japanese for justice, and koko is for “here, a place close to me/ us.” So what this is really saying is:

“Justice is with us!”

It’s not just saying that Justice exists, it’s saying Justice is here, with us.

Example 2: “Hito ga iru yo!”

The “yo” is a particle used for emphasis. Let’s say a small group of young people… oh, imagine it’s a Scooby Doo cartoon or something… and they are searching a run-down house. Suddenly, there is the sound of footsteps from a nearby corridor.

“There’s somebody here!”

It’s not just the existence, it’s the presence.

As I like to keep saying, Japanese isn’t some strange, alien language. It just needs to be explained in an intelligent way and understood on its own terms, not our skewed Western expectations.

Incidentally, “desu” is not generally placed after “iru” or “aru,” not because of grammatical reasons per se, but because Japanese, culturally, is a need-to-know language. Because both “iru” and “aru” require existence to be, if you will, priced into the market, since nothing can be present without first existing, there’s no need to affirm the existence; it’s implicitly affirmed. So “desu” (or “da” or any other variety) would be redundant. – J

J Sensei

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2 Responses to Japanese: Aru, Iru, and Desu

  1. Dec says:

    Very clearly and concisely explained. ありがとうございます。

  2. ありがとうございます！:D
    I’ve just learned いる and ある and it was confusing because ,,a long” time ago I’ve learned です. But now everything is clear. 😀

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