場合はIn case / if
場合は names a possible situation and then states the rule, response, or result that applies in that case. It is especially useful for instructions, notices, troubleshooting, and contingency plans.
A case followed by its response
The part before 場合は defines the relevant case. The rest of the sentence then gives the instruction, consequence, rule, or fact that applies specifically to that case.
Typical procedural uses
These examples name a contingency first and then give the appropriate response.
Choose the form that describes the case
The verb form before 場合 matters. A past form can describe something that has already happened by the time a response is needed, while a negative form defines a case in which something does not happen or cannot be done. The main sentence may still be polite even though the form directly before 場合 is plain.
A negative case
予約を変更しない場合は、連絡は不要です。
If you are not changing the reservation, there is no need to contact us.
AnalyzeCase-based and conversational conditions
場合は packages the premise as a defined case, so it fits manuals, policies, notices, and organized advice. たら is more conversational and often presents one event followed by another. なら more directly responds to a premise or topic already under discussion.
More examples
雨が降る場合は、式を体育館で行います。
If it rains, the ceremony will be held in the gym.
Analyze参加できない場合は、前日までに知らせてください。
If you cannot attend, please let us know by the previous day.
Analyze荷物が重い場合は、二人で運んでください。
If the package is heavy, please have two people carry it.
Analyze学生の場合は、学生証を見せてください。
If you are a student, please show your student ID.
Analyze追加の説明が必要な場合は、担当者にお問い合わせください。
If you need further explanation, please contact the person in charge.
Analyze万一、警報が鳴った場合は、すぐに建物の外へ避難してください。
In the unlikely event that the alarm sounds, evacuate the building immediately.
Analyze