Usage of ～じゃん (～じゃない)


I'd like to know if I can put ～じゃん at the end of every adjective, if there are
any exceptions to that usage, and if it's different from ～じゃない.

**Adj (na) + じゃん**

> 便利 **じゃん**
>
> 便利だった **じゃん**
>
> 便利じゃない **じゃん**
>
> 便利じゃなかった **じゃん**

**Adj (i) + じゃん**

> 楽しい **じゃん**
>
> 楽しかった **じゃん**
>
> 楽しくない **じゃん**
>
> 楽しくなかった **じゃん**

Is this possible? Wouldn't the correct way would be 楽しくない instead of 楽しいじゃん?

**Verb + じゃん**

> ある **じゃん**
>
> やる **じゃん**
>
> いる **じゃん**
>
> くる **じゃん**
>
> ...




The first thing to understand here is that じゃん forms a [tag
question](http://en.wikipedia.org/wiki/Tag_question), so it's entirely
different than the negative form:

> このゲームは楽しい。 This game is fun.
>
> このゲームは楽しいじゃん。 This game is fun, isn't it?
>
> このゲームは楽しくない。 This game isn't fun.
>
> このゲームは楽しくないじゃん。 This game isn't fun, is it?

じゃん is an informal version of じゃない; this use of じゃない as a tag question was
[covered by Tsuyoshi Ito
previously](https://japanese.stackexchange.com/questions/453/expression-in-
spoken-japanese/505#505).

Since 形容詞 (けいようし; "い-adjectives") have different conjugation patterns than
形容動詞 (けいようどうし; "な-adjectives"), you can easily tell when a tag question is
being used. But you know that with 形容動詞, じゃない may be present in the negative
form. Without additional context, the following could be ambiguous:

> 便利じゃない。 It's not convenient. **Or** , It's convenient, isn't it?

In this example, intonation distinguishes tag questions from negatives: a tag
question will put a rising intonation on じゃない, while a negative will put a
falling intonation on じゃない. (じゃん, however, is always a tag question and never
forms a negative.)

In writing, this ambiguity can be cleared up by using a question mark or the
question particle か:

> 便利じゃない？ It's convenient, isn't it?
>
> 便利じゃないか。 It's convenient, isn't it?

Additionally, it's worthwhile to discuss here the difference between じゃない
(じゃん) as a tag question and the sentence-ending particle ね:

> あの映画、けっこうおもしろかったね。 That movie was pretty good, wasn't it?
>
> あの映画、けっこうおもしろかったじゃん。 That movie was pretty good, wasn't it?

With ね, the speaker is merely making a statement and anticipating the listener
will agree, but じゃん can often imply that the speaker wants to convince the
listener to agree. In the above example, you would use the first sentence
after seeing a movie with a friend without any prior expectation of how good
the movie would be. But the second is more appropriate if, for example, your
friend went into the movie thinking it would be bad, and after seeing it, you
wanted to get him to agree with you that it was in fact a good movie.




The first thing to understand here is that じゃん forms a [tag
question](http://en.wikipedia.org/wiki/Tag_question), so it's entirely
different than the negative form:

> このゲームは楽しい。 This game is fun.
>
> このゲームは楽しいじゃん。 This game is fun, isn't it?
>
> このゲームは楽しくない。 This game isn't fun.
>
> このゲームは楽しくないじゃん。 This game isn't fun, is it?

じゃん is an informal version of じゃない; this use of じゃない as a tag question was
[covered by Tsuyoshi Ito
previously](https://japanese.stackexchange.com/questions/453/expression-in-
spoken-japanese/505#505).

Since 形容詞 (けいようし; "い-adjectives") have different conjugation patterns than
形容動詞 (けいようどうし; "な-adjectives"), you can easily tell when a tag question is
being used. But you know that with 形容動詞, じゃない may be present in the negative
form. Without additional context, the following could be ambiguous:

> 便利じゃない。 It's not convenient. **Or** , It's convenient, isn't it?

In this example, intonation distinguishes tag questions from negatives: a tag
question will put a rising intonation on じゃない, while a negative will put a
falling intonation on じゃない. (じゃん, however, is always a tag question and never
forms a negative.)

In writing, this ambiguity can be cleared up by using a question mark or the
question particle か:

> 便利じゃない？ It's convenient, isn't it?
>
> 便利じゃないか。 It's convenient, isn't it?

Additionally, it's worthwhile to discuss here the difference between じゃない
(じゃん) as a tag question and the sentence-ending particle ね:

> あの映画、けっこうおもしろかったね。 That movie was pretty good, wasn't it?
>
> あの映画、けっこうおもしろかったじゃん。 That movie was pretty good, wasn't it?

With ね, the speaker is merely making a statement and anticipating the listener
will agree, but じゃん can often imply that the speaker wants to convince the
listener to agree. In the above example, you would use the first sentence
after seeing a movie with a friend without any prior expectation of how good
the movie would be. But the second is more appropriate if, for example, your
friend went into the movie thinking it would be bad, and after seeing it, you
wanted to get him to agree with you that it was in fact a good movie.

