Do You Need to Reply Within 24 Hours?How to Handle Emails at Night and on Weekends.

Are you unsure about the timing of your business emails in Japan?

Maybe you’re thinking:

• “My Japanese grammar is perfect, but I’m not sure when to hit send…”
• “Is it rude to reply late at night?”
• “What should I do if I’m too busy to reply right away?”

If you work for a Japanese company or do business with Japanese partners, you’ve likely faced these dilemmas.

In the Japanese business world, emails are more than just a communication tool—they are a way to build and maintain trust with your colleagues and clients.

To help Japanese language learners send emails with confidence, this article breaks down two essential points:

• The “24-Hour” Response Rule
• Etiquette for Nights and Weekends

＼Japanese business etiquette／
「日本で働くためのビジネス基礎講座きそこうざ」

Replying Within 24 Hours

In Japanese business etiquette, you should always strive to reply to emails within 24 hours.

Why within 24 hours?

The main reason is to avoid wasting the other person’s time.

In Japan, work is rarely a solo effort; it’s usually a team process.

If you don’t reply, everyone else involved is left waiting and unable to take the next step.

When a reply is slow, the other person might start to worry:

• “Are they ignoring me?“
• “Did my email even arrive?“

• “Maybe this project isn’t a priority for them?“

Does a fast reply leave a good impression?

On the other hand, replying quickly sends a clear message: “Your business is a priority to us,” and “We value our relationship with you.”

Additionally, people who respond promptly are often perceived as highly competent and reliable professionals.

To help you stay on track, here is a guide to ideal response speeds:

• Within 3 hours: Exceptional (Creates a great impression!)
• Within 24 hours: Standard business etiquette.
• 2 days or more: An apology for the delay is necessary.

What if you can’t reply right away?

Even if you are aware of the “24-hour rule,” there will be times when you’re simply too busy to provide a full response.

In such cases, the best approach is to send a quick “acknowledgment” email to let them know you’ve received it.

If you stay silent because you can’t provide a “perfect” answer yet, the other person might start to worry: “Did my email get lost?” or “Are they ignoring me?”

To avoid causing this anxiety, make it a priority to simply say, “I’ve received your message.”

For example, you could write something like this:

①感謝かんしゃ	お世話せわになっております。資料しりょうをお送りいただき、ありがとうございます。
②返信できない理由	現在げんざい、担当部署たんとうぶしょにて確認かくにんを行おこっております。
③返信期限きげん	追おって※、明日あす1月がつ25日にち（水すい）の午前中ごぜんちゅうまでに改あらためてご連絡れんらく差さし上あげます。
④締しめの言葉	取とり急いそぎ※、拝受はいじゅ※のご連絡れんらくまで申もうし上げます。どうぞよろしくお願ねがいいたします。

※「追おって」：Later on/After a while

※「取とり急いそぎ」：I’m sending this quick update just to cover the most important point first.

※「拝受はいじゅ」：I have received./Confirming receipt.

①感謝かんしゃ	お世話せわになっております。ご連絡れんらくありがとうございます。
②返信できない理由	いただいたご提案ていあんについて、現在上司げんざいじょうしと協議きょうぎしております。
③返信期限きげん	今週中こんしゅうちゅうには結論けつろんが出でる予定よていですので、確定次第かくていしだい、早急そうきゅうにご報告ほうこくいたします。
④締しめの言葉	今いましばらくお時間じかんをいただけますと幸さいわいです。どうぞよろしくお願ねがいいたします。

①感謝かんしゃ	お世話せわになっております。お問とい合あわせの件けん、確たしかに承知しょうちいたしました。
②返信できない理由	あいにく※本日ほんじつ終日しゅうじつ外出がいしゅつしており、すぐにお答こたえすることが難むずしい状況じょうきょうです。
③返信期限きげん	明日会社あすかいしゃに戻もどり次第しだい、詳細しょうさいを確認かくにんしご連絡れんらくいたします。
④締しめの言葉	お待またせして恐縮きょうしゅくですが、何卒なにとぞよろしくお願ねがい申もうし上あげます。

※「あいにく」：Unfortunately/I’m afraid

Even if you can’t address the issue or provide an answer immediately, send a quick reply just to acknowledge that you’ve received the email.

Etiquette for sending emails at night or on weekends

In Japan, more and more people are prioritizing their work-life balance.

However, there are still times when you might find it necessary to work late at night or over the weekend.

In those situations, it is important to be mindful that contacting someone during their off-hours might put pressure on them.

It’s best to write your email with a touch of consideration for the recipient’s personal time.

1. Start with a brief apology

In Japanese business culture, it is common to start by apologizing for intruding on the other person’s time.

2. State that a reply is not urgent

To avoid making the recipient feel rushed or pressured to reply immediately, show some consideration for their time. Including a simple phrase like this will greatly improve the impression you leave.

The Japanese perspective on work

In Japan, many people feel that “receiving an email equals having unfinished work,” which can be a significant source of stress.

Sending an email on a Friday night or right before a long holiday might weigh on the recipient’s mind throughout their time off.

Conclusion: Emails are a tool for building “Trust”

In Japanese business etiquette, using perfect grammar isn’t the only thing that matters.

The common thread between these two points is the Japanese spirit of “Omoiyari”—putting yourself in the other person’s shoes.

A prompt response or a thoughtful short note can be the key to building a strong professional relationship where people think, “I really want to work with this person!”

It might feel a bit overwhelming at first, but try using the phrases we introduced today and take it one step at a time. You’ve got this!

To help you overcome these challenges, mailun-lab offers specialized learning materials for Japanese business email writing.

If you found this helpful, feel free to explore our other articles below:

”Business Japanese Email Materials" by Former HR & Teacher | mailun-labStruggling with Japanese business emails? Perfect for JLPT N3+ learners, our materials created by an ex-HR expert cover not just phrases, but the cultural logic behind them. Improve your professional skills with our self-study guides. Subscribe today for a free "Basics" textbook!...