[good first issue] 🍜 Add new Japanese Idiom 591 (good-first-issue)
This issue is a "good first issue" that invites contributors to add a new Japanese idiom to a JSON file. The task involves no coding and can be completed directly in the browser by forking the repository, editing the specified JSON file, and submitting a pull request. It's designed for absolute beginners and should take less than a minute.