Help with validating Japanese encoded pages

Japanese encoding:

In my content type meta tag I have tried specifying Windows-31J, Shift-JIS 
and x-sjis  and with all three my site fails to validate in XHTML 1.0. 
I went to the valid character sets page on the W3C site and even when 
specifying those my page is unable to validate. If you could give me any 
feedback on how to use Japanese encoding and successfully validate I would 
greatly appreciate it.

When using x-sjis I get the following error:

        Sorry! A fatal error occurred when attempting to transcode the 
character encoding of the document. Either we do not support this 
character encoding yet, or you have             specified a non-existent 
character encoding (often a misspelling). 
        The detected character encoding was "x-sjis".
        The error was "x-sjis undefined; replace by shift_jis".

Otherwise I get this error(s):

        shift_jis:
        Sorry, I am unable to validate this document because on line 83 it 
contained one or more bytes that I cannot interpret as shift_jis (in other 
words, the bytes                found are not valid values in the 
specified Character Encoding). Please check both the content of the file 
and the character encoding indication. 

        windows-31j:
        Sorry! A fatal error occurred when attempting to transcode the 
character encoding of the document. Either we do not support this 
character encoding yet, or you have             specified a non-existent 
character encoding (often a misspelling). 
        The detected character encoding was "windows-31j".
        The error was "".