Learn Hardcore Japanese: watasi ha itido nihon ni ikitai desu.

は marks the topic of the sentence: what we’re talking about.
が usually marks the grammatical subject, especially when introducing something new or focusing on who did something.

In this sentence:

私は一度日本に行きたいです。
→ “As for me, I want to go to Japan once.”

Using は makes 私 the general topic: “speaking about me…”.
If you said 私が一度日本に行きたいです, it would sound like you’re contrasting yourself with others or emphasizing “I’m the one who wants to go” (e.g., not someone else). That nuance is usually unnecessary here, so は is the normal choice.

Can I leave out 私 (watashi)? Would the sentence still be correct?

Yes. In natural Japanese, the subject is often omitted when it’s clear from context. You could simply say:

一度日本に行きたいです。
→ “(I) want to go to Japan once.”

This is very natural, especially in a conversation where it’s already clear that you’re talking about yourself.
You might explicitly say 私 if:

You’re introducing yourself for the first time.
You want to contrast with someone else (e.g., “I want to go, but my friend doesn’t”).
You’re practicing and want to see the full structure.

What exactly does 一度 (ichido) mean here? Is it “once” or “sometime”?

Literally, 一度 means “once / one time”.

In this sentence, it has two overlapping nuances:

Literal: “I want to go to Japan once (at least one time).”
Idiomatic: It often carries a softer, “sometime (in my life)” feeling, similar to:
- “I’d like to go to Japan at least once.”
- “I’d like to go to Japan someday (at least once).”

So it keeps the idea of “at least one time,” but in many contexts it feels like “someday, at least once in my life.”
If you want a more open-ended “someday” without the “once” nuance, you can also say:

いつか日本に行きたいです。
→ “I want to go to Japan someday.”

Why is 日本 followed by に (ni)? What does に do here?

に is a particle with several uses; one of them is to mark the destination of movement.
With verbs like 行く (to go), 来る (to come), 帰る (to return), you usually use に (or へ) to show where you’re going.

日本に行きたいです。
→ “I want to go to Japan.”

So here に = “to (a place)” in English.
Note: に can also mean “in/at/on” for locations and times, but in this sentence it’s the destination marker.

What’s the difference between 日本に and 日本へ? Can I say 日本へ行きたいです instead?

You can absolutely say:

日本へ行きたいです。

Both are correct and natural.

に vs へ with motion verbs:

に focuses more on the destination as a place you end up at.
へ focuses more on the direction / movement toward that place.

In modern everyday Japanese, 日本に行きたいです is more common, but 日本へ行きたいです does not sound strange.
In many basic sentences, you can treat them as more or less interchangeable, and に is a bit safer as a default.

Why is it 行きたいです (ikitai desu) and not something like 行くたいです?

The base verb is 行く (iku) = “to go”.

To say “want to do X” with most verbs, Japanese uses the 〜たい form:

Take the ます-stem of the verb.
- 行く → 行き (this is the same stem used in 行きます)
Add たい.
- 行き + たい → 行きたい = “want to go”

So:

❌ 行くたい – incorrect form
✅ 行きたい – correct “want to go”

Then to make it more polite, you can add です, because 〜たい behaves like an i-adjective:

行きたい (casual)
行きたいです (polite)

Is 行きたいです “I want to go” or “I would like to go”? Is it strong or soft?

Literally, 行きたいです is “(I) want to go.”

However, nuance-wise:

In polite Japanese, 〜たいです is not as blunt as “I WANT to …!” in English.
It’s usually felt as a normal, polite way to express your desire: somewhere between “I want to go” and “I’d like to go.”

If you want to be even softer or more indirect, you might use patterns like:

日本に行けたらいいなと思います。
“I think it would be nice if I could go to Japan.”
日本に行ってみたいです。
“I’d like to try going to Japan (at least once).”

But in most everyday contexts, 日本に行きたいです is already polite and not overly pushy.

Why is です (desu) at the end? Isn’t 行きたい already a verb form?

行きたい is based on the verb 行く, but 〜たい itself behaves grammatically like an i-adjective (like うれしい, たのしい, etc.).

Casual: 行きたい。
Polite: 行きたいです。

Adding です:

makes the sentence polite (です/ます style),
is standard for talking to strangers, teachers, in most formal situations.

So 行きたいです is simply the polite form of 行きたい. Both are correct; which one you use depends on formality and relationship with the listener.

Is the word order fixed? Can I say 日本に一度行きたいです instead of 一度日本に行きたいです?

Both are possible:

一度日本に行きたいです。
日本に一度行きたいです。

In this sentence, both sound natural. Japanese word order is relatively flexible; the crucial part is usually:

verb at the end: …行きたいです

Elements like 一度 (once) and 日本に (to Japan) can swap positions without changing the meaning much.

Subtle nuance:

一度日本に行きたいです。
Slightly emphasizes “once (in my life), to Japan…”
日本に一度行きたいです。
Slightly emphasizes “to Japan, once…”

But in everyday conversation, the difference is minor; both are fine.

How do you pronounce each part of the sentence?

私 – わたし (watashi)
は (topic marker) – pronounced わ (wa), not ha
一度 – いちど (ichido)
日本 – commonly にほん (Nihon); にっぽん (Nippon) is also correct but used in specific contexts (e.g. official names, cheering). Here にほん is more usual.
に – に (ni)
行きたい – いきたい (ikitai)
です – usually pronounced です (desu), with the u very weak or almost silent in natural speech: sounds close to des.

Does 私 (watashi) make this sound feminine? What would men usually say?

私 (watashi) is:

gender-neutral in polite speech (men and women both use it),
slightly more common for women in casual speech, but that’s more about informality.

In a polite context, a man can naturally say:

私は一度日本に行きたいです。

In casual or very informal speech, men often switch to:

僕 (ぼく) – common, softer:
僕は一度日本に行きたい。
俺 (おれ) – rougher / more masculine:
俺は一度日本に行きたい。

So the sentence as given is perfectly fine for any gender in polite situations.

How would I make this negative, like “I don’t want to go to Japan”?

Use the negative of the 〜たい form:

行きたい → 行きたくない (“don’t want to go”)

Polite form:

行きたくないです or 行きたくありません

So the full negative sentence is:

私は日本に行きたくないです。
→ “I don’t want to go to Japan.”

(Again, 私 can be omitted if it’s clear from context.)