But who cares about them, right? That’s right, Tokyo all the way man. Whoo hoo! Sure people are cold and rude here but at least they don’t get into your business. And plus, Osaka is like a tiny, tiny version of Tokyo. (Let the flames begin!)

Ahem. Anyway, now that I got my usual pointless introduction out of the way, I once heard that 「じゃん」 was originally part of a regional dialect from… somewhere. Whether that’s true or something I just made up, this little expression has spread to gain enormous popularity in Tokyo and probably throughout the rest of the Kanto region and beyond. (I purposely made that vague because I have no idea how far this expression extends. But I’m sure it’s pretty far.)

In any case, it’s common enough that I decided to write a little about it describing what it means and how to use it. If you live in the Kansai region all I have to say is, “Ha Ha! You suck!”. But still, since you’ll hear this slang all the time in TV and movies, why don’t you just go ahead and read the rest of this post instead of hating me because I said you suck.

On a side note, I’d like to mention that this is one of those topics that is easier to explain verbally but for now, I’m just going to go with a written explanation. I leave it up to you to get out into the Japanese speaking world to learn how this expression actually sounds in real life.

Ok ok, get to the point!

Simply put, 「じゃん」 is an abbreviation of 「じゃない」, the negative conjugation for nouns and na-adjectives. However, this only applies to 「じゃない」 used in the following fashion.

１）サラリーマンだから、残業はたくさんするんじゃない？
-Because [he’s] a salaryman, doesn’t [he] do a lot of overtime?

The important thing to note about the example above is that 「じゃない」 here is actually confirming the positive. In fact, a closer translation is, “Because he’s a salaryman, he probably does a lot of overtime.” But it’s still a question so there’s a slight nuance that you are seeking confirmation even though you are relatively sure.

「じゃん」 is a shorter slang for expressing the same type of thing except it doesn’t even bother to ask a question to confirm. It’s completely affirmative in tone.

In fact, the closest equivalent to 「じゃん」 is 「じゃない」 used in the following fashion.

１） まあ、いいじゃない。
– Well, it’s probably fine (don’t you think?).

This type of expression is the only case where you can attach 「じゃない」 directly to i-adjectives and verbs. Once you actually hear this expression in real life, you’ll see that it has a distinct pronunciation that is different from simply using the negative. Plus, you have to realize that this type of 「じゃない」 sounds rather mature and feminine, unlike 「じゃん」, which is gender-neutral (and arguably inclined toward younger speakers). (Ha! And you thought Japanese was easy!)

Like the above, specialized use of 「じゃない」, you can also attach 「じゃん」 directly to verbs and i-adjectives as well as the usual nouns and na-adjectives. Because slang is usually created to make things easier, it’s not surprising that the rules for using 「じゃん」 are so lax and easy.

Finally, let’s get to the examples. Hopefully, you can see that 「じゃん」 is basically saying something along the lines of, “See, I’m right, aren’t I?”

１） ほら、やっぱりレポートを書かないとだめじゃん。
-See, as I thought, [you] have to write the report.

２） 誰もいないからここで着替えてもいいじゃん。
-Since there’s nobody, it’s probably fine to change here.

Example Conversation
A） たかしくんは、ここにいる？ – Is Takashi here?
B） 知らない。- Dunno.
A) あっ！やっぱ、いるじゃん！- Ah! See, he is here!

There’s also another variation which attaches the question marker as well. The meaning is mostly the same but it adds more to the questioning, confirming tone.

A) 駅の近くにカラオケがあるじゃんか。- There’s a karaoke place near the station, right?
B) うん。- Yeah.
A) あそこのすぐ隣だ。- It’s right next to there.

Summary

So, let’s recap on what 「じゃん」 is and how it’ s used.

1. Though derived from 「じゃない」, 「じゃん」 is always used to confirm the positive.
2. It can be attached to the end of any sentence regardless of whether it ends in a noun, adjective, verb, or adverb.

Ok, the explanation was confusing but actually using 「じゃん」 should be a piece of cake!