japanese email subject encoding

Question

Aparently, encoding japanese emails is somewhat challenging, which I am slowly discovering myself. In case there are any experts (even those with limited experience will do)

Answer 1

First of all you should be using:

Encoding.GetEncoding("ISO-2022-JP")

to convert your subject line into bytes that will be processed by Convert.ToBase64String().

=?ISO-2022-JP?B?TEXTTEXT...?= tells the receiving mail client which encoding was used on the sender's side to convert japanese "letters" into a byte stream.

Currently you're using UTF-16 to encode, but specifying ISO-2022-JP to decode. These are obviously two different encodings, I guess, just like ISO-8859-1 is different from Unicode (most extended western-europe chars are represented by one byte in ISO-XXX, but two bytes in Unicode).

I'm not sure what you mean about UTF-8 being second-class citizen. As long as the receiving mail client understands UTF-8 and is able to convert it to the current japanese locale, everything is fine.