motikomi ha kanou da.

持ち込み is a noun form derived from the verb 持ち込む, which means to bring in or to bring something into a place.

In this sentence, 持ち込み means something like:

• bringing in outside items
• bringing your own food/drink/items
• outside items being brought in

Japanese often turns verbs into noun-like forms this way. So instead of saying the action as a verb, it treats it as a concept or category.

• 持ち込む = to bring in
• 持ち込み = bringing in / carry-in / outside food and drink, depending on context

So 持ち込みは可能だ is literally closer to As for bringing things in, it is possible.

It is the ます-stem form of the verb:

• dictionary form: 持ち込む
• polite form: 持ち込みます
• stem: 持ち込み

This stem can often act like a noun.

Examples of the same pattern:

• 読み from 読む = reading
• 休み from 休む = rest / holiday
• 申し込み from 申し込む = application

So here, 持ち込み is a noun-like expression meaning bringing in.

は marks 持ち込み as the topic.

So the sentence has the structure:

• 持ち込み = bringing things in
• は = as for...
• 可能だ = is possible / is allowed

A natural literal interpretation is:

• As for bringing things in, it is possible.

Using は gives a sense of speaking about that category/topic. This is common in notices, rules, and short written statements.

Yes, 持ち込みが可能だ is also possible, but the nuance is slightly different.

• 持ち込みは可能だ: As for bringing things in, it is possible.
  • topic-oriented
  • often feels like regarding this matter
• 持ち込みが可能だ: Bringing things in is possible.
  • more directly marks 持ち込み as the thing that is possible

In many real contexts, both can work. But は is especially common when contrasting or discussing a rule/topic, such as:

• 店内での飲食は不可だが、持ち込みは可能だ。
• Eating inside is not allowed, but bringing things in is allowed.

可能 is a noun or na-adjective meaning:

• possible
• feasible
• allowed, depending on context

In rule-like sentences, it often sounds a bit formal or written. So 持ち込みは可能だ can mean:

• Bringing items in is possible
• You may bring items in
• Carry-ins allowed

The exact English translation depends on context. In signs and announcements, it often ends up meaning allowed rather than just possible.

だ is the plain copula, roughly like is in English.

So:

• 可能だ = is possible

Because 可能 is noun-like / na-adjective-like, it needs the copula in plain style when ending a sentence.

Compare:

• plain: 可能だ
• polite: 可能です
• negative: 可能ではない
• past: 可能だった

So the full sentence is a plain-style statement.

It is plain style, but that does not necessarily mean casual.

持ち込みは可能だ often sounds:

• concise
• matter-of-fact
• written
• rule-like
• notice-board style

For example, it would fit well in:

• signs
• policy descriptions
• FAQs
• written instructions

If you wanted a polite spoken version, you could say:

• 持ち込みは可能です。

That is often more natural in conversation or customer service.

They are similar, but not always identical in tone or usage.

• できる often means can do
• 可能だ often means is possible / is permitted / is feasible

For this sentence:

• 持ち込みは可能だ
• 持ち込める

Both can relate to possibility, but they are used differently.

持ち込める focuses more directly on the verb to bring in:

• You can bring it in

持ち込みは可能だ sounds more like:

• Bringing items in is permitted/possible
• a policy statement

So 可能だ is often more formal and more common in rules or posted notices.

Yes, but it changes the feel.

• 持ち込みは可能だ = rule/policy style
• 持ち込める = direct verbal possibility

Examples:

• ここは飲み物を持ち込める。
  • You can bring drinks in here.
• 飲み物の持ち込みは可能だ。
  • Bringing drinks is allowed here.

The second one sounds more formal and typical of written policies.

Japanese often leaves the subject unstated when it is obvious from context.

So 持ち込みは可能だ does not explicitly say:

• who is bringing something in
• what exactly is being brought in
• where it is being brought in

Those details are understood from the situation.

Depending on context, it could mean:

• customers may bring in outside food
• visitors may bring bags inside
• participants may bring their own equipment

This kind of omission is very normal in Japanese, especially in short rule statements.

It depends on context, but in real life it very often refers to bringing outside items into a place, especially:

• food
• drinks
• alcohol
• personal equipment

For example:

• 飲食物の持ち込み
  • bringing in food and drinks
• 酒類の持ち込み
  • bringing in alcohol

On signs, 持ち込み可 or 持ち込み可能 often means outside items allowed, especially food and drink.

So the exact nuance comes from the setting.

Yes. Japanese, especially in notices and rule statements, often drops anything that can be understood.

A fuller sentence might be something like:

• この場所では持ち込みは可能だ。
• At this place, bringing things in is allowed.

Or more specifically:

• 飲み物の持ち込みは可能だ。
• Bringing drinks in is allowed.

But in many contexts, just 持ち込みは可能だ is enough.

Japanese frequently prefers this compressed style when the surrounding context already tells you the rest.

A common polite version is:

• 持ち込みは可能です。

Depending on the situation, other natural polite expressions include:

• 持ち込みできます。
• 持ち込みが可能です。
• お持ち込みいただけます。
  
  • more polite / service-oriented
• 持ち込みしていただけます。
  • possible in some contexts, but less elegant than the others

For a sign or customer-facing notice, 持ち込みは可能です is very natural.

Very common variations include:

• 持ち込み可能
  • even shorter sign style: carry-ins allowed
• 持ち込み可
  • 可 means permitted
• 持ち込みは可
  • more formal/notice-like
• 持ち込みは禁止です
  • bringing items in is prohibited
• 持ち込みはできません
  • you cannot bring items in
• 飲食物の持ち込みは可能です
  • bringing in food and drinks is allowed

Japanese signs often shorten things heavily, so you may see just:

• 持ち込み可
• 持ち込み不可

These are extremely common.

Yes, and this is important.

Grammatically, 可能 means possible. But in many practical contexts, especially signs and policies, the natural English is often allowed.

So depending on context:

• literal: Bringing things in is possible.
• natural policy translation: Outside items are allowed.
• more specific: You may bring in your own food and drinks.

So even if the Japanese literally says possible, the intended meaning may really be permitted.

That is very common with words like 可能, 不可, and 可 in notices.