Days of the Week in Japanese

The seven days at a glance

Japanese day names follow one simple pattern: a single kanji, then 曜日 (ようび). The first kanji does all the work, so learning the week really means learning seven characters, most of which are among the first kanji any beginner meets.

Notice that 日 appears twice in Sunday. The first 日 is read にち and means the sun, while the final 日 is read び and means day. The same character can have several readings depending on the word, which is the core idea explained in onyomi vs kunyomi. In the day names, every first kanji uses its Chinese-derived on'yomi: げつ, か, すい, もく, きん, ど, にち.

Why the days are named after the sun, moon and five elements

The Japanese week uses the same idea as the European one: each day is named after one of seven visible heavenly bodies. English keeps traces of this in Sunday, Monday and Saturday. In Japanese the five visible planets are named after the five Chinese elements, so the link is easier to see:

• 日 (sun) for Sunday and 月 (moon) for Monday, as in English.
• 火 (fire) for Mars, 火星 (かせい), so Tuesday.
• 水 (water) for Mercury, 水星 (すいせい), so Wednesday.
• 木 (wood) for Jupiter, 木星 (もくせい), so Thursday.
• 金 (metal) for Venus, 金星 (きんせい), so Friday.
• 土 (earth) for Saturn, 土星 (どせい), so Saturday.

If you know French or Spanish, the match is even clearer: Tuesday is mardi or martes (Mars), Wednesday mercredi or miércoles (Mercury), Thursday jeudi or jueves (Jupiter) and Friday vendredi or viernes (Venus). The planetary week reached Japan through China around the year 800, traditionally credited to the monk Kūkai (Kōbō Daishi), and the diaries of the courtier Fujiwara no Michinaga show it in use by 1007. For centuries it was used mainly for astrology, and it only became part of everyday civil life in the Meiji era, when Japan adopted a Western-style calendar.

Memory hooks for each kanji

Most of these kanji are simple pictures, which makes them some of the easiest characters to remember. A few hooks that work well:

• 月 (4 strokes): a crescent moon drawn upright, with two lines across it. Monday is moon day, as in the English name.
• 火 (4 strokes): a small fire with sparks flying off both sides. Tuesday is when things heat up.
• 水 (4 strokes): a central stream with water splashing left and right. Wednesday, the middle of the week, is where things flow.
• 木 (4 strokes): a tree with branches above and roots below. Thursday has wood.
• [金](/kanji/金) (8 strokes): a roof over a mound with two gold nuggets inside. Friday is payday in many places, so think gold.
• 土 (3 strokes): a sprout pushing up out of the ground. Saturday is for the garden.
• 日 (4 strokes): a sun in a frame. Sunday is sun day in both languages.

The shared part, 曜 (よう), is harder: it has 18 strokes and on its own just means day of the week. You will mostly read it rather than write it, but if you want to practice it, the kanji stroke order tool animates each stroke, and the stroke order rules explain why the left-hand 日 comes first.

Asking and saying what day it is

The question word is 何曜日 (なんようび, what day of the week). A short exchange looks like this:

• 今日は何曜日ですか。(きょうは なんようび ですか, What day is it today?)
• 月曜日です。(げつようび です, It is Monday.)
• 金曜日に会いましょう。(きんようび に あいましょう, Let's meet on Friday.)

Use the particle に when something happens on a specific day, as in 金曜日に. In casual speech the final 日 is often dropped, so you will hear 月曜 (げつよう) or 金曜 (きんよう) as well as the full forms. Both are correct, and the full form is the safer choice when you are unsure.

Week words that go with the days

A handful of related words lets you talk about schedules. Most of them use 週 (しゅう, week):

• 今週 (こんしゅう): this week
• 先週 (せんしゅう): last week
• 来週 (らいしゅう): next week
• 毎週 (まいしゅう): every week, as in 毎週土曜日 (every Saturday)
• 週末 (しゅうまつ): the weekend
• 平日 (へいじつ): weekdays, Monday to Friday
• 土日 (どにち): Saturday and Sunday together, a very common way to say the weekend

These words also show how the day kanji combine. 土日 simply joins the first kanji of Saturday and Sunday, and timetables use the same trick, such as 月水金 (げつすいきん) for Monday, Wednesday and Friday classes.

Spotting the day on calendars, receipts and signs

In real life you will rarely see the full 月曜日 written out. Dates in Japan usually put the first kanji of the day in parentheses after the date, so 10月26日(月) means Monday, October 26. You will see this on receipts, train tickets, event posters, emails and appointment cards, which makes these seven kanji some of the most useful ones to know in Japan.

Shop hours and timetables often use them too: a sign saying 定休日 水曜日 (ていきゅうび すいようび) means the shop is regularly closed on Wednesdays, and 土日祝 (どにちしゅく) means Saturdays, Sundays and public holidays. Wall calendars commonly color 日 in red and 土 in blue, so you can find the weekend at a glance. Those two colors, 赤 and 青, are explained in the colors in Japanese guide.

All seven day kanji, plus 曜 and 週, are part of the JLPT N5 kanji, so they are a natural first set to learn alongside numbers and the dates built from them. Moji tracks kanji from JLPT N5 to N1 with spaced repetition reviews and can show them on your Lock Screen, which suits characters you will meet every day anyway.

Say the day in Japanese every time you look at a calendar or your phone's date. Seven words, repeated daily, stick within a week or two.