LESSON NOTES · レッスンノート

N5Lesson notes · Oct 4, 2026

Moon in Japanese: 月つき (つき), 満月まんげつ, and what 月つきが綺麗きれいですね really means

"Moon" in Japanese is 月つき (つき, tsuki). A full moon is 満月まんげつ (まんげつ), a crescent moon is 三日月みかづき (みかづき), and the same kanji 月がつ also means "month" and gives Monday its name: 月曜日げつようび (げつようび), "moon day".

月がつ is one of the first kanji most learners write, usually because of dates. That makes it easy to forget it is also the moon, and that the moon carries a lot of culture in Japan: an autumn moon-viewing season, a rabbit pounding rice cakes on its surface, a princess who came from it, and a sentence that the internet has turned into a secret "I love you". This post covers the word, its three readings, the moon phases, and those stories, including how much of the famous one is actually true.

How do you say "moon" in Japanese?

What is the basic word?

月つき (つき) is the everyday word for the moon. You can also hear お月つき様さま (おつきさま), a soft, slightly childlike form, like "Mr. Moon".

今夜こんやは月つきがきれいだ。 — The moon is beautiful tonight. (casual, looking at the sky) 月つきが雲くもに隠かくれた。 — The moon went behind the clouds. (neutral, describing) お月つき様さまが出でているよ。 — The moon is out. (gentle, often said to children)

The katakana ムーン appears in names and titles, like セーラームーン, but nobody uses it for the real moon in conversation.

Why does 月がつ also mean "month"?

Because the old calendar followed the moon, one moon cycle became one month. When 月がつ means "month", it is usually read がつ or げつ. A few native words keep つき for "month" too, such as 月つきに一回いっかい (つきにいっかい, once a month) and ひと月がつ (ひとつき, one month).

Reading Meaning Example
つき the moon 月つきがきれい
がつ month name 一月いちがつ (いちがつ), January
げつ month, Monday 一いちか月げつ (いっかげつ), one month; 月曜日げつようび

私わたしの誕生日たんじょうびは三月さんがつです。 — My birthday is in March. (polite, がつ for month names) 日本にほんに一いちか月げついました。 — I was in Japan for a month. (polite, げつ for a length of time)

The rule of thumb: names of months use がつ, lengths of time use かげつ, and the moon itself is つき. Our post on days of the week and dates shows the full calendar set.

Why is Monday "moon day"?

月曜日げつようび (げつようび) is literally "moon day of the week", the same idea as English "Monday". Japanese uses the sun, the moon and five planets for its week, so 日曜日にちようび is "sun day".

月曜日げつようびは忙いそがしいです。 — Mondays are busy. (polite, small talk)

Beyond the basics

What are the words for full moon and crescent moon?

The phases each have a word, and most use the げつ reading.

Word Reading Meaning
新月しんげつ しんげつ new moon
三日月みかづき みかづき crescent moon
半月はんつき はんげつ half moon
満月まんげつ まんげつ full moon
月光げっこう げっこう moonlight

今夜こんやは満月まんげつです。 — Tonight is a full moon. (polite) 細こまい三日月みかづきが見みえる。 — I can see a thin crescent moon. (neutral)

三日月みかづき means "third-day moon", the thin moon seen about three days after the new moon. 月光げっこう is mostly written or poetic; in conversation people say 月つきの光ひかり (つきのひかり).

What is お月見つきみ?

お月見つきみ (おつきみ) is moon viewing, a custom in autumn when people admire the bright moon with dumplings and pampas grass. The night is called 十五夜じゅうごや (じゅうごや), and its moon is the 中秋ちゅうしゅうの名月めいげつ (ちゅうしゅうのめいげつ), "the famous moon of mid-autumn".

今年ことしのお月見つきみはいつですか。 — When is moon viewing this year? (polite) お月見つきみ団子だんごを食たべた。 — I ate moon-viewing dumplings. (casual)

The date follows the old lunar calendar, so it moves each year, usually landing in September or early October. The word 月見つきみ also shows up on menus: 月見つきみうどん and 月見つきみそば have a raw egg on top, the yellow yolk standing in for the moon, and fast-food chains sell 月見つきみバーガー with a fried egg every autumn.

Is there really a rabbit on the moon?

In Japanese folklore, yes: the dark patches on the moon are a rabbit pounding rice cakes.

月つきでうさぎが餅もちをついている。 — A rabbit is pounding mochi on the moon. (neutral, the story told to children)

Where English speakers see a "man in the moon", Japanese children are taught to see a rabbit with a mallet. It is why rabbits appear in so much autumn and moon-themed design. 餅もちをつく (もちをつく) is the verb for pounding mochi.

Who came from the moon?

かぐや姫ひめ (かぐやひめ), the princess in Japan's oldest surviving tale, 竹取物語たけとりものがたり (たけとりものがたり). A bamboo cutter finds a tiny girl inside a glowing bamboo stalk. She grows into a famous beauty, turns down every suitor, and finally returns to her home on the moon.

かぐや姫ひめは月つきに帰かえった。 — Princess Kaguya returned to the moon. (neutral, the ending everyone knows)

Studio Ghibli made a film of it, かぐや姫ひめの物語ものがたり (The Tale of the Princess Kaguya), and the name かぐや turns up in many other anime and manga too.

What does 月つきが綺麗きれいですね mean?

Literally "The moon is beautiful, isn't it?", but online it is famous as a hidden way to say "I love you". The story goes that the novelist 夏目漱石なつめそうせき (なつめそうせき), while teaching English, told a student that a Japanese person would never say "I love you" directly and should say this instead.

月つきが綺麗きれいですね。 — The moon is beautiful, isn't it. (polite, a real comment, or a coded confession)

The line uses the plain 綺麗きれい rather than 美うつくしい, and Japanese words for beautiful explains that 美うつくしい is weightier and rarer in speech, so きれい is what a person would actually say.

Here is the honest part: there is no reliable record that Sōseki ever said this. The story appears much later, and it is best treated as a legend. It still lives on because it captures something real about how indirect Japanese affection can be. Anime and manga use it as a confession scene, and many Japanese people will recognize it. If you say it to someone, though, they may simply agree that the moon is nice. We cover the bigger picture in I love you in Japanese.

How does anime use 月がつ?

Two famous examples: a magical girl's catchphrase and a thriller's main character.

月つきにかわっておしおきよ! — In the name of the moon, I'll punish you! (the classic セーラームーン line)

The other is 夜よる神月こうづき in デスノート (Death Note), whose given name 月がつ is read ライト, "Light". It is a deliberately unusual reading, and it shows how freely names in fiction bend kanji. Real given names use 月がつ too, as in 美月みつき (みづき), usually with a softer reading.

Common mistakes

  • Reading 月がつ as つき in a date. 三月さんがつ is さんがつ, not さんつき.
  • Mixing up がつ and かげつ. 三月さんがつ (さんがつ) is March. 三さんか月げつ (さんかげつ) is three months.
  • Using ムーン for the real moon. It sounds like a product name. Say 月がつ.
  • Saying 月つきが綺麗きれいですね and expecting it to work as a confession. It is a known reference, not a code everyone will catch.
  • Reading 三日月みかづき as みっかづき. It is みかづき.

Quick comparison

Word Reading Meaning
月がつ つき moon
お月つき様さま おつきさま Mr. Moon (soft, childlike)
満月まんげつ まんげつ full moon
三日月みかづき みかづき crescent moon
月見つきみ つきみ moon viewing
月曜日げつようび げつようび Monday
三月さんがつ / 三さんか月げつ さんがつ / さんかげつ March / three months

Practice

Try each answer yourself before opening it. Questions 3 and 4 are a pair: the same kanji, two readings, two meanings.

1. Say "The moon is beautiful tonight" casually.

Show answer

今夜こんやは月つきがきれいだ — 月がつ is read つき when it means the moon.

2. What is a full moon in Japanese?

Show answer

満月まんげつ (まんげつ) — 満まん means "full".

3. How do you read 三月さんがつ, and what does it mean?

Show answer

さんがつ, March — month names use がつ.

4. How do you read 三さんか月げつ, and what does it mean?

Show answer

さんかげつ, three months — a length of time uses かげつ. This is the pair to question 3.

5. Which day of the week is 月曜日げつようび?

Show answer

Monday — literally "moon day", read げつようび.

6. What is the thin moon a few days after the new moon called?

Show answer

三日月みかづき (みかづき) — "third-day moon", the crescent.

7. What is the autumn custom of admiring the moon called?

Show answer

お月見つきみ (おつきみ) — often with dumplings, on the night called 十五夜じゅうごや.

8. In Japanese folklore, what is on the moon?

Show answer

A rabbit pounding mochi — 月つきでうさぎが餅もちをついている.

9. Which princess returned to the moon at the end of her story?

Show answer

かぐや姫ひめ — from 竹取物語たけとりものがたり, Japan's oldest surviving tale.

10. Is it historically proven that 夏目漱石なつめそうせき translated "I love you" as 月つきが綺麗きれいですね?

Show answer

No — there is no reliable record. It is a popular legend that captures how indirect Japanese affection can be.

In a trial lesson, describe tonight's moon with 満月まんげつ or 三日月みかづき, and ask what 月つきが綺麗きれいですね really means.

FAQ

What is the hiragana for moon? つき. In names or poetry you may see other readings, but つき is the word.

How do you say "moon" as a name? Japanese names often use 月がつ with readings like つき or づき, as in 美月みつき (みづき). Ask the person how they read their name, since readings vary.

What is the difference between 月がつ and お月つき様さま? They are the same moon. お月つき様さま is the soft, affectionate form, often in children's songs and stories. In normal conversation, just say 月がつ.

What do people reply to 月つきが綺麗きれいですね? In the romantic version, a popular reply is 死しんでもいいわ, "I could die happy". The phrase is linked to an old literary translation, but pairing it with the moon line is a modern internet custom, so enjoy it as part of the legend.

What is moonlight in Japanese? 月つきの光ひかり (つきのひかり) in conversation, or 月光げっこう (げっこう) in writing and titles.

Why are there eggs in 月見つきみうどん? The round yolk on top looks like a full moon over clouds of noodles, so the dish borrows the moon-viewing name.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

月	つき — moon
お月様	おつきさま — Mr. Moon (soft)
満月	まんげつ — full moon
新月	しんげつ — new moon
半月	はんげつ — half moon
三日月	みかづき — crescent moon
月光	げっこう — moonlight (written)
月の光	つきのひかり — moonlight
お月見	おつきみ — moon viewing
十五夜	じゅうごや — night of the autumn full moon
中秋の名月	ちゅうしゅうのめいげつ — the mid-autumn moon
月曜日	げつようび — Monday
一か月	いっかげつ — one month
餅をつく	もちをつく — to pound mochi
かぐや姫	かぐやひめ — Princess Kaguya

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from lines I've actually heard students ask about. The 月つきが綺麗きれいですね story is one learners bring up again and again, and it is a good door into how readings of 月がつ change. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons; standard Japanese dictionaries; 竹取物語たけとりものがたり (public-domain classical text).

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N5 · Read something at this level: JLPT N5 stories with audio

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