yubune ni hairu mae ni, kakeyu wo wasure naide hosii.

• 湯船 is read ゆぶね
• かけ湯 is read かけゆ

A quick breakdown:

• 湯 = hot water
• 船 = boat, vessel, tub-like container → in 湯船, it refers to the bathtub/tub filled with hot water
• かけ湯 = pouring hot water over your body before entering the bath

So both words are very common in bathhouse or hot spring contexts.

Not exactly.

• 湯船 means the actual tub of hot water that you soak in.
• お風呂 can mean the bath, bath time, the bathroom, or bathing in general, depending on context.

In this sentence, 湯船 is used because the focus is specifically on entering the tub itself, not just bathing in general.

So:

• 湯船に入る = get into the tub
• お風呂に入る = take a bath / get in the bath

They can overlap, but 湯船 is more specific.

The に marks the destination or target of movement.

With 入る, the place you enter is marked by に:

• 部屋に入る = enter the room
• おふろに入る = get into the bath
• 湯船に入る = get into the tub

So 湯船に入る literally means enter the bathtub.

Because with 前に, Japanese usually uses the plain form of the verb to describe the action that has not happened yet.

Pattern:

• Verb dictionary form + 前に = before doing ...
• 食べる前に = before eating
• 寝る前に = before sleeping
• 湯船に入る前に = before getting into the tub

This makes sense logically: at the point of before, the action has not happened yet, so Japanese uses the non-past/plain form.

前 can mean either:

1. before in time
2. in front of in space

In this sentence, it means before because it follows a verb phrase:

• 湯船に入る前に = before getting into the tub

When 前 follows a verb or event, it usually refers to time.

Compare:

• 駅の前 = in front of the station
• 出かける前 = before going out

So the grammar around it tells you which meaning it has.

In 前に, the に marks the time point at which something should happen.

So:

• 湯船に入る前に、かけ湯を忘れないでほしい means
• Before entering the tub, I want you not to forget the rinsing/pouring hot water step

You will often see:

• 食事の前に = before the meal
• 寝る前に = before sleeping
• 行く前に = before going

Sometimes 前 appears without に, but 前に is very common and natural here.

かけ湯 is the act of pouring warm or hot water over your body before entering a bath, especially in a public bath or hot spring.

It is done:

• to clean yourself lightly
• to help your body adjust to the water temperature
• to keep the bath water clean

So this sentence reflects a common bathing rule or expectation in Japan.

Because を marks the direct object of 忘れる.

The thing being forgotten is かけ湯.

So:

• かけ湯を忘れる = forget the rinsing step / forget to do かけ湯

Even though English often says forget to do X, Japanese can simply say X を忘れる when X is treated like a thing, step, or task.

This is a very important pattern.

Break it down:

• 忘れる = to forget
• 忘れないで = don’t forget
• ほしい = want

But ないでほしい does not mean want not forgetting in a strange literal sense. As a pattern, it means:

• Verb-ないでほしい = I want you not to do ...
• 忘れないでほしい = I want you not to forget

So the full sentence means:

• Before getting into the tub, I want you not to forget to do かけ湯

It is a way of expressing the speaker’s wish or expectation about another person’s action.

They are similar, but the nuance is different.

• 忘れないでください = Please don’t forget.
• 忘れないでほしい = I want you not to forget.

So:

忘れないでください

• a direct request
• polite
• common in signs, instructions, and service language

忘れないでほしい

• expresses the speaker’s desire or hope
• can sound a little more personal
• depending on context, it may sound softer, more emotional, or sometimes less like a formal public notice

In a bathhouse sign, 忘れないでください might sound more standard.
But 忘れないでほしい can still be used if the writer wants a slightly warmer or more personal tone.

It is somewhat polite in tone, but not fully formal.

Why:

• ほしい by itself is plain form
• there is no です or ください
• however, the wording is still gentle rather than blunt

So it feels like:

• a soft reminder
• a friendly request
• a mildly personal instruction

If you wanted to make it more formally polite, you could say:

• 湯船に入る前に、かけ湯を忘れないでほしいです。 or more directly:
• 湯船に入る前に、かけ湯を忘れないでください。

The subject is omitted, which is very normal in Japanese.

The implied meaning is usually:

• I/we want you to not forget to do かけ湯

So the hidden structure is something like:

• （私は／私たちは）あなたに かけ湯を忘れないでほしい。

But Japanese often leaves out:

• the person who wants something
• the person being addressed

because the context makes it clear.

In a sign or instruction, the understood meaning is usually:

• We want bath users to remember this

Yes, absolutely.

Japanese often says:

• 忘れないでほしい = I want you not to forget

But natural English often prefers:

• Please remember to ...
• Be sure to ...

So a very natural English rendering would be:

• Before getting into the tub, please remember to rinse yourself with hot water first.

That is often smoother than a very literal translation like:

• Before entering the tub, I want you not to forget the rinsing water.

Good question. Japanese often allows a noun to stand for an action or step.

So:

• かけ湯を忘れないでほしい literally treats かけ湯 as the thing not to forget

This is similar to English expressions like:

• Don’t forget your homework
• Don’t forget your medicine
• Don’t forget the introduction

Even though what you really mean is don’t forget to do/use it.

A more explicit version would be:

• かけ湯をするのを忘れないでほしい = I want you not to forget to do かけ湯

But the original sentence is shorter and very natural.

It is not grammatically required, but it is helpful.

The comma separates:

• the time-setting phrase: 湯船に入る前に
• the main request: かけ湯を忘れないでほしい

So it makes the sentence easier to read:

• Before entering the tub, ...

Japanese commas are often used more flexibly than English commas, especially to make long sentences easier to process.

In this sentence, it clearly sets the timing for the whole main statement.

It means:

• At the time before entering the tub, I want you not to forget to do かけ湯

So the structure is:

• 湯船に入る前に = before entering the tub
• かけ湯を忘れないでほしい = I want you not to forget the rinsing step

This kind of sentence-opening time phrase is very common in Japanese. It works much like English Before ..., please ....