Make sure to select Japanese JIS (Shift-JIS) and MIME format in your mailer settings. 

• Corrupted text
  When your email text is corrupted, first check if the character code of your mailer is Japanese JIS. If the email is still unreadable with Japanese JIS, the sender may have a problem. The recipient needs to fix the code to a correct one using a code conversion tool. 
• Different transfer methods between mailers
  There are several transfer methods (standards for sending data) for email.
  Normally, mailers use Multipurpose Internet Mail Extension (MIME) in text format. Both the sender and the recpient must be using the normal format.
  If HTML, 8bit, or UUENCODE is being used, the data may not be sent successfully.
  Please note that settings are different depending on the mailer you use. Consult the manufacturer of your mailer.
• Corrupted subject
  When the subject is corrupted, the following may be considered.
  Usually, it is desirable that the subject of an internet email is written in half-width alphanumeric characters. However, the subject can be in Japanese language if your mailer supports MIME. If the subject is corrupted, MIME may not be specified in your mailer, or MIME is not supported by your mailer.
• If email is sent/received with an OS in different language
  If you are using Windows or Mac in Japanese language and receive an email from Windows or Mac in different language, characters not in Japanese or alphabet cannot be shown correctly.
  In this case, it is basically difficult to solve the problem if you do not use an OS which supports the respective language. For details, please contact the manufacturer of your OS.