Learn Hardcore Japanese: tuuro ni nimotu wo oite ha ikemasen. - You must not put luggage in the aisle.

に often marks:
- A point in space where something exists or ends up.
- A goal or target of an action (where you put something).
で marks:
- The place where an action is performed.

In 通路に荷物を置く, the passageway (通路) is the final location where the luggage ends up. You are not focusing on doing the action in the passageway, but on putting something onto/in the passageway as a result.

So:

通路に荷物を置く = to place luggage in/on the passageway (putting it there).
通路で荷物を置く would sound like “to do the action of placing luggage in the passageway,” which is odd and not natural here.

For placing/putting something somewhere, [place]に[object]を置く is the normal pattern.

Why is there no word for “you” in this sentence?

Japanese often omits the subject when it is obvious from context.

On signs, announcements, and rules, Japanese normally uses just the verb phrase in a prohibitive form, like:

～てはいけません
～てはだめです

These have an implicit general subject, roughly “you / people / anyone”. So:

通路に荷物を置いてはいけません。
→ “[You] must not put luggage in the passageway.”

Saying あなたは通路に荷物を置いてはいけません is grammatically OK but feels too direct or accusatory for a public rule. Japanese prefers the impersonal style here.

What does 荷物を do in the sentence?

荷物 means “luggage,” “baggage,” or “baggage items.”
を marks the direct object of the verb.

荷物を置く = “to put/place luggage (down).”

Japanese does not mark plural with s, so 荷物 can mean:

“luggage” (uncountable),
“a piece of luggage,”
or “luggage items,” depending on context.

What exactly is 置いては? Why not just 置きます?

置いては is:

置いて = the て‑form of 置く (to put/place).
は = the particle that attaches to the て‑form to make a prohibition pattern: ～てはいけません.

The pattern is:

[verb in て‑form] + は + いけません

So:

置く → 置いて
置いて + はいけません → 置いてはいけません.

You cannot say 置きますはいけません. The prohibition grammar specifically uses the て‑form, not the polite ～ます form.

Is the は in 置いては the same as the topic marker は?

It is the same particle は, but here it plays a contrastive/limiting role, not a sentence‑level topic.

In ～てはだめ, ～てはいけません, the nuance is:

“[Doing X], as for that, is not allowed / not good.”

So in 置いては, the は emphasizes that this action (placing/putting) is what is being disallowed.
It is not introducing the main sentence topic like in 私は学生です; it is tightly bound to the て‑form to create a prohibition pattern.

What does ～てはいけません literally mean, and how strong/polite is it?

Literally:

いけません comes from 行く (to go), and in this set phrase it has the sense “is no good / will not do.”
～てはいけません is roughly “If (you) do X, that will not do / is not acceptable.”

Natural English equivalents:

“You must not do X.”
“You are not allowed to do X.”

Politeness/strength:

～てはいけません: polite, somewhat formal; used on signs, in instructions, by teachers, etc.
～てはいけない: plain style; still a strong “must not.”
～てはだめです: a bit softer, everyday speech (“That’s not okay.”).
～ちゃだめ / ～ちゃいけない (from ～ては → ～ちゃ): casual, spoken.

On a public sign, ～てはいけません is a standard, polite but firm prohibition.

Could you say 通路に荷物を置いてはだめです instead? What’s the difference?

Yes, 通路に荷物を置いてはだめです is grammatically fine and means essentially the same thing: “You must not put luggage in the passageway.”

Nuance:

～てはいけません
- More formal/polished.
- Very typical for written rules and signs.
～てはだめです
- Slightly more casual, feels like spoken guidance or admonition.
- Still polite, but not as “official sign”‑like.

On a sign in a station or airport, ～てはいけません is more natural.
In conversation (e.g., staff warning someone), ～てはだめですよ might sound more natural.

Could this sentence be reordered as 荷物を通路に置いてはいけません? Is that still correct?

Yes, that word order is also correct:

荷物を通路に置いてはいけません。

Japanese word order is relatively flexible as long as:

The verb comes last, and
Particles (に, を, etc.) stay attached to the right nouns.

Both:

通路に荷物を置いてはいけません。
荷物を通路に置いてはいけません。

are natural.
(1) slightly emphasizes the place (passageway).
(2) slightly emphasizes the object (luggage).
For a sign about blocking the passageway, version (1) is very typical because it foregrounds 通路.

Why use 置いてはいけません instead of 置かないでください?

Both express not doing something, but with a different feel:

置いてはいけません
- A rule/prohibition: “You must not put (it there).”
- Stronger, sounds like a regulation or official instruction.
- Common on signs, in manuals, in classroom rules.
置かないでください
- A polite request: “Please do not put (it there).”
- Softer, more like someone is asking you personally.
- Common in spoken requests, service situations.

On a rule sign in a building, ～てはいけません fits better because it states a general prohibition, not just a personal request.

What is the literal meaning of いけません here?

いけません is the polite negative form of いける, which in this fixed usage derives from 行く (to go).

Historically and literally, in this set phrase it means something like:

“(It) cannot go (that way).”
“(It) won’t do; (it) is not acceptable.”

In modern Japanese, learners should remember it simply as:

いけません = “is no good / must not / not allowed.”

So 置いてはいけません = “(Doing) the action of placing (it there) is not acceptable.”

How polite is this whole sentence? Where would you typically see it?

The sentence uses:

The polite form いけません.
No casual contractions (like ～ちゃだめ).

So it is polite and neutral‑formal. You would typically see this style:

On public signs (stations, airports, malls).
In written instructions or rule lists.
In announcements in public spaces.

It’s not overly stiff, but it is clearly not casual speech.

How should は be pronounced in 置いては?

In this sentence:

は is pronounced “wa”, not “ha.”

General rule:

When は is used as a particle (topic marker, contrastive は, or in patterns like ～ては), it is written は but pronounced wa.
When は is part of a word (like はな “nose/flower”), it is pronounced ha.

So:

置いては → おいては (pronounced oitewa).