Why some friends can read my Japanese email while others can't?

It has a lot to do with the programs you and your friends are using when sending and receiving emails in Japanese. Some programs will strip off some "high-bit" Japanese codes while transmitting the message and we can not do much about these programs. However, there is a safe way to do this:
 

  1. write in NJSTAR Japanese WP,
  2. save as Shift-JIS file.
  3. attached the file in your email.

your receiver should not have any problem opening and reading the attached Shift-JIS file.