If you use Mac OS X in English (by setting “English” as primary language in “International” of System Preferences, you might have been experiencing issues with sending Japanese e-mails. In Japan, most of the popular webmail services handle text in ISO-2022-JP while Apple’s Mail sends UTF-8-encoded text. As a result, recipients of your e-mail may see garbage text contrary to your expectation.
The solution for this is simple, open Terminal and type in
defaults write com.apple.mail NSPreferredMailCharset "ISO-2022-JP"
Done. Now, your mail client uses ISO-2022-JP encoding. No worries about using the same mail client for sending to non-Japanese people. Popular e-mail software just handle ISO-2022-JP encoding. No setup for your recipients.
