際/折/時 (Formal 'When') in Japanese

Overview

While you learned とき (toki) at the A2 level for expressing "when," Japanese has several more formal and literary alternatives for the same concept. At B2, you encounter 際 (sai), 折 (ori), and advanced uses of 時 that appear in formal writing, business communication, polished speech, and literary contexts.

These expressions are not interchangeable — each carries a distinct register and nuance. 際 is the standard formal alternative to とき, common in business and official contexts. 折 is more literary and suggests a fortunate or timely occasion. Understanding when to reach for each one is an important part of developing your formal Japanese ability.

These patterns appear frequently in business emails, formal announcements, customer service interactions, and written instructions. While you may not use them daily in casual conversation, recognizing and producing them is essential for professional fluency.

How It Works

際 (sai) — Formal "When/On the Occasion of"

The most common formal replacement for とき. Used in business, official documents, and polite instructions.

Structure	Example
Noun + の際	出発の際 (upon departure)
Verb (dictionary form) + 際	申し込む際 (when applying)
Verb (た form) + 際	お越しになった際 (when you came)
この際	on this occasion / while we're at it

折 (ori) — Literary "Occasion/Opportunity"

More literary and softer than 際. Implies a favorable or notable occasion.

Structure	Example
Noun + の折	帰国の折 (on the occasion of returning home)
Verb (dictionary form) + 折	お会いする折 (when we meet)
この折	on this occasion
折に触れて	from time to time / on various occasions

Advanced 時 Patterns

Beyond basic とき, more sophisticated patterns exist.

Pattern	Meaning	Register
時には	sometimes / on occasion	neutral-formal
〜の時点で	at the point/time of	formal, precise
いざという時	when it really matters	set expression
〜した時点では	at the time when	formal narrative

Comparison

Expression	Register	Nuance	Common Context
とき	neutral	general "when"	everyday speech
際	formal	"on the occasion of"	business, instructions
折	literary/formal	"at the opportunity of"	letters, polished speech
時点で	formal/technical	"at the specific point of"	reports, analysis

Examples in Context

Japanese	English	Note
お越しの際は、ご連絡ください。	Please contact us when you come.	際 — business polite
帰国の折には、お立ち寄りください。	Please drop by when you return to the country.	折 — literary polite
困った時はいつでも相談してください。	Please consult me whenever you're in trouble.	時 — warm, direct
この機会に申し上げたいことがあります。	I have something to say on this occasion.	機会 — formal opportunity
ご利用の際は、身分証明書をお持ちください。	Please bring ID when using (our services).	際 — instructions
お会いできた折には、改めてお礼を申し上げます。	When we meet, I will thank you properly.	折 — formal letter
契約の際に、署名が必要です。	A signature is required at the time of the contract.	際 — official
いざという時に備えて、保険に入りましょう。	Let's get insurance for when the time comes.	Set expression
この際、はっきり言わせてもらいます。	While we're at it, let me speak frankly.	この際 — "now's the time"
申し込みの時点で、キャンセルはできません。	At the point of application, cancellation is not possible.	時点 — precise timing
折に触れて、思い出します。	I remember from time to time.	折に触れて — set phrase

Common Mistakes

Using 際 in casual conversation

• Wrong: コンビニに行く際に、ジュースを買ってきて。 (to a friend)
• Right: コンビニに行く時に、ジュース買ってきて。
• Why: 際 is formal and sounds stiff in casual contexts. Use とき with friends and family. Reserve 際 for business and formal situations.

Confusing 際 and 折

• Wrong: 非常の折には、この出口を使ってください。 (emergency instructions)
• Right: 非常の際には、この出口を使ってください。
• Why: 折 implies a welcome or notable occasion. Emergency instructions require the neutral-formal 際. You would not describe an emergency as a favorable "occasion."

Incorrect particle usage with 際

• Wrong: 出発する際で
• Right: 出発する際に or 出発の際に
• Why: 際 takes the particle に (at the time of). Using で is incorrect. The pattern is always 際に or 際は.

Usage Notes

際 is by far the most common of these formal alternatives in modern Japanese. You will encounter it in every business email, public announcement, and instruction manual. It has become so standard in formal contexts that using とき in its place can sound too casual.

折 carries an elegant, somewhat old-fashioned tone. It appears frequently in formal letters, especially seasonal greetings and thank-you notes. The set phrase 折に触れて (from time to time) is worth memorizing as a whole unit.

この際 has developed a special conversational meaning: "while we're at it" or "now that we're on the subject." It signals a shift to a new topic or a decision to address something directly: この際だから、言うけど (since we're on the topic, I'll say it).

In formal writing, 時点 (jiten) is preferred when precise timing matters, such as legal documents or technical reports. It is more specific than 際 and emphasizes the exact moment rather than the general occasion.

Practice Tips

• Rewrite five casual sentences using とき, replacing them with 際. For example: 日本に行く時 → 日本にお越しの際. This trains you to switch registers naturally.

• Read business emails or formal announcements in Japanese and circle every instance of 際, 折, and 時点. Notice which contexts each appears in and build your intuition for appropriate usage.

• Practice writing a short formal letter using 折: thank someone for a visit (先日はお越しの折、大変お世話になりました) or express hope for a future meeting (お会いできる折を楽しみにしております).

Related Concepts

• Prerequisite: とき (when) — the basic "when" pattern that these formal alternatives build upon
• Next steps: Formal Written Style — broader formal writing conventions including である体