The author has less experiences with NEmacs 3.0. So, the following description may be wrong. If you find any mistakes, please let the author know (see section Reporting Bugs).
In NEmacs 3.0, the kanji code of articles stored in the NNTP server
must be specified according to both the service name (or number) and the
host name running the server. For this, the function
define-service-kanji-code is provided.
The following example specifies the kanji code of the host `flab' as JIS using this function:
(define-service-kanji-code "nntp" "flab" 2) ;2 stands for JIS.