Google Analytics Data API should be capable of handling multibyte characters like Japanese in event names. However, the “Bad Request” error you’re encountering may be related to incorrect encoding, misconfiguration, or the API doesn’t understand the request due to incorrect syntax. Please double-check the request you’re sending to ensure it is properly formatted and encoded. If you’re using a library or module to interact with the API, ensure it supports multibyte characters. Alternatively, there could be a bug or limitation in the API itself. In this case, you might want to contact Google support or look for documentation about handling multibyte characters.