kono hausubooru, karui zyan.

In casual spoken Japanese, the topic particle は is often omitted when it is obvious.

So this sentence is essentially:

• このハウスボールは、軽いじゃん。

But in natural conversation, people often drop は and just say:

• このハウスボール、軽いじゃん。

This makes it sound more conversational and spontaneous.

じゃん is a very casual sentence-ending expression. It often adds a feeling like:

• See?
• Told you
• Isn’t it?
• Wow, it really is...

In this sentence, 軽いじゃん has the feeling of noticing or pointing out something obvious to the listener, like:

• This house ball is light, isn’t it?
• Wow, this house ball is light.

It often invites agreement from the other person.

No. Even though じゃん historically comes from a form related to じゃない, it usually does not make the sentence negative.

So:

• 軽いじゃん

does not mean isn’t light.

Instead, it means something like:

• It’s light, you know
• It’s light, isn’t it?

This is a very common point of confusion for learners.

軽い is the plain dictionary form of the い-adjective 軽い meaning light.

Here it is being used as the main predicate of the sentence:

• このハウスボール、軽い。
• This house ball is light.

Adding じゃん keeps 軽い in that same plain form:

• このハウスボール、軽いじゃん。

You do not use 軽く here, because 軽く is the adverbial form, used in patterns like:

• 軽くなる = become light
• 軽く持つ = hold lightly

この means this and directly modifies the noun that follows it.

So:

• このハウスボール = this house ball

A key rule is:

• この must be followed by a noun
• これ stands alone

So you can say:

• このハウスボール = this house ball
• これは軽いじゃん。 = This is light, isn’t it?

But you cannot say このは軽い.

ハウスボール is a katakana loanword, from English house ball.

In bowling, it refers to a ball provided by the bowling alley, not your personal ball.

So this sentence sounds like something someone might say while trying a bowling ball at the alley.

Yes, very casual.

There are two big clues:

• omission of は
• use of じゃん

This sounds like everyday spoken Japanese between friends, family, classmates, etc.

A more polite version might be:

• このハウスボールは軽いですね。
• このハウスボール、軽いですね。

A somewhat less casual but still conversational version could be:

• このハウスボール、軽いじゃないですか。

By itself, じゃん is not strongly masculine or feminine. It is widely used by all kinds of speakers, especially in casual conversation.

What matters more is:

• age
• region
• level of casualness
• the rest of the person’s speech style

So learners should mainly think of it as casual spoken Japanese, not as a specifically male or female ending.

The comma marks a pause after the topic-like part:

• このハウスボール、 / light, isn’t it?

It helps separate:

• what you are talking about
• what you are saying about it

In speech, there is often a small pause there. In writing, the comma makes that pause visible.

It is not absolutely required every time, but it is very natural.

No. Standard Japanese writing normally does not use spaces between words.

So the normal written form is:

• このハウスボール、軽いじゃん。

The spaced version is usually just for learners, to make the parts easier to see.

Yes. A fuller version would be:

• このハウスボールは軽いじゃん。

That is grammatically fine. But in natural speech, dropping は often sounds more relaxed and immediate.

So:

• このハウスボールは軽いじゃん。 = a bit more explicit
• このハウスボール、軽いじゃん。 = very natural casual speech

Both are understandable, but the version without は feels especially conversational.

It sounds like the speaker has just noticed something and is reacting to it, often expecting the listener to agree.

Depending on tone, it could feel like:

• mild surprise
• confirmation
• pointing something out
• reminding someone of something obvious

So the vibe is less like a neutral textbook statement and more like:

• Hey, this house ball is light.
• See? This house ball is light.
• Wow, this house ball is pretty light, isn’t it?

That conversational nuance is an important part of why じゃん is used.