kinou-vs-ashita

When you first start learning Japanese, time words like きのう (yesterday) and あした (tomorrow) feel simple enough. But once you dig deeper, you discover that Japanese has multiple ways to express these concepts — some formal, some casual, and some surprisingly poetic. This guide covers everything you need to know about きのう (kinou) and あした (ashita), including their kanji, related time expressions, and how to use them naturally in conversation.

At a Glance: きのう vs あした

きのう (昨日) — Yesterday

きのう means “yesterday” — the day immediately before today. It is written with the kanji 昨日, where 昨 means “previous/last” and 日 means “day/sun.” You will almost always use past-tense verb forms (～ました / ～た) when きのう appears in a sentence.

Formal alternative: In formal writing, news broadcasts, or business settings, you may see or hear さくじつ (昨日, sakujitsu). The kanji is identical — only the reading changes. きのう is perfectly fine in polite (です/ます) speech as well.

Example sentence 1:

きのう映画を見ました。
Kinō eiga o mimashita.
I watched a movie yesterday.

Example sentence 2:

きのうは何をしていたの？
Kinō wa nani o shite ita no?
What were you doing yesterday?

Example sentence 3 (formal/written):

昨日、重要な会議がありました。
Sakujitsu, jūyō na kaigi ga arimashita.
There was an important meeting yesterday.

あした (明日) — Tomorrow

あした means “tomorrow” — the day immediately after today. The kanji 明日 combines 明 (bright, clear) and 日 (day/sun), giving the sense of “the bright day ahead.” You will pair あした with present or future-intention verb forms (～ます / ～つもり / ～予定).

Alternate reading: あした can also be read as あす (asu). あす is slightly more literary or formal, and you will often hear it in weather forecasts: 「あすの天気は晴れでしょう。」 (Tomorrow’s weather will be sunny.) In everyday conversation, あした is more natural.

Formal alternative: みょうにち (明日, myōnichi) is the highly formal reading used in business correspondence and formal announcements.

Example sentence 1:

あした友達に会います。
Ashita tomodachi ni aimasu.
I will meet a friend tomorrow.

Example sentence 2:

あしたは早起きしなきゃ。
Ashita wa hayaoki shinakya.
I have to wake up early tomorrow.

Example sentence 3 (formal):

明日の会議の準備ができています。
Myōnichi no kaigi no junbi ga dekite imasu.
The preparations for tomorrow’s meeting are complete.

Japanese Time Vocabulary: The Full Picture

きのう and あした are part of a broader set of time-reference words in Japanese. Learning them together helps you navigate conversations about the past and future with confidence.

Common Mistakes English Speakers Make

Mistake 1: Using the wrong tense with time words
In English, “Yesterday I go to school” is clearly wrong — you must use past tense. Japanese works the same way. Always use past-tense verb forms (～ました / ～た) with きのう, and present/future forms (～ます / ～つもり) with あした. Mixing tenses with time words is a very common beginner error.

Mistake 2: Forgetting あす as an alternative for あした
You will hear あす (asu) in weather forecasts and radio news. If you only know あした, あす can sound unfamiliar. Remember: both mean “tomorrow,” with あす being slightly more formal or literary.

Mistake 3: Placing time words at the end of the sentence
In English, time words often go at the end: “I went to the park yesterday.” In Japanese, time words typically come at the beginning of the sentence or right after the topic: きのう公園に行きました (Kinō kōen ni ikimashita). While placing them at the end is not always wrong, starting with the time word is more natural and natural-sounding.

Decision Flowchart: きのう or あした?

Use this flowchart whenever you are unsure which word to use:

Which day are you talking about?
├─ The day BEFORE today → Use きのう (昨日)
│　　├─ Casual/polite speech → きのう (kinō)
│　　└─ Formal writing / news → さくじつ (sakujitsu)
├─ Today → Use きょう (今日)
└─ The day AFTER today → Use あした (明日)
　　　├─ Casual/polite speech → あした (ashita)
　　　├─ Literary / forecast → あす (asu)
　　　└─ Formal business → みょうにち (myōnichi)

Quick Quiz

Fill in the blank with きのう or あした. Answers and explanations below.

1. ___、学校を休みました。(___, I was absent from school.)

2. ___、映画を見に行こう！(Let’s go see a movie ___!)

3. ___何を食べましたか？(What did you eat ___?)

4. ___のパーティーが楽しみです。(I’m looking forward to ___’s party.)

5. ___は雨でした。(It was raining ___.)

Answers:

1. きのう — 休みました is past tense, so it refers to yesterday.
2. あした — 行こう is a volitional form suggesting a future plan.
3. きのう — 食べましたか is past tense polite form.
4. あした — パーティーが楽しみです expresses anticipation of a future event.
5. きのう — でした is past tense, so the rain happened yesterday.

きのう and あした are among the most useful words you will ever learn in Japanese — they come up in nearly every conversation. Master the formal alternatives (さくじつ, みょうにち) and you will sound polished in any situation, from casual chat to business meetings.

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