折にはOn the occasion of
折に and 折には formally identify a noteworthy or suitable occasion for an action. They are especially natural when a visit, meeting, trip, or later opportunity provides the setting for a courteous request, offer, promise, or report.
Choosing between the two forms
折に simply locates an action at the relevant occasion. Adding は makes that occasion the topic: “when that opportunity arises.” This makes 折には especially well suited to courteous language about what someone should, may, or will do then.
Typical formal contexts
Notice how each occasion is significant enough to support the elevated wording.
当館を訪れる折には、事前にご予約くださいますようお願いいたします。
When visiting our museum, we kindly ask that you make a reservation in advance.
AnalyzeA future occasion is framed as the opportunity for a courteous request.
次回お越しの折には、私が館内をご案内いたします。
The next time you visit, I will show you around the building.
AnalyzeThe noun pattern introduces a polite promise tied to a future visit.
昨年、京都でお目にかかった折に、貴重なお話を伺いました。
When I met you in Kyoto last year, I had the opportunity to hear your valuable insights.
AnalyzeThe past verb form identifies a completed formal occasion.
お忙しい折にご対応いただき、誠にありがとうございました。
Thank you very much for assisting us despite your busy schedule.
AnalyzeThis established courteous phrasing uses an i-adjective to describe the circumstances.
Not just a formal replacement for every “when”
とき is the broad, neutral choice for everyday time references, including routine events and ordinary mishaps. 際に is also formal, but it is particularly common when locating an action within a situation, procedure, or set of instructions. By contrast, 折に more readily presents the time as a noteworthy or suitable occasion. These are tendencies rather than absolute divisions.
More examples
次に東京へいらっしゃる折には、ぜひ研究室へお立ち寄りください。
The next time you come to Tokyo, please do stop by the laboratory.
Analyze新年度を迎える折に、改めて方針をご説明申し上げます。
As we enter the new fiscal year, I will explain the policy again.
Analyze前任地に赴任した折に、多くの方々から温かいご支援をいただきました。
When I took up my post at my previous assignment, I received warm support from many people.
Analyzeご多忙の折に、迅速にご回答いただきありがとうございました。
Thank you for responding promptly despite your busy schedule.
Analyze都合のよい折に、改めてご連絡いただければ幸いです。
I would appreciate it if you could contact me again when convenient.
Analyze海外へ出張する折には、現地の担当者にもご挨拶いたします。
When I travel overseas on business, I will also pay my respects to the local representative.
Analyze