>>>>> In <86vh4xx5v9.fsf@mediawars.ne.jp> 
>>>>>	Shigeki Uno <shigeki@mediawars.ne.jp> wrote:
 
>> (setq mm-body-charset-encoding-alist
>>       '((iso-2022-jp . 7bit) (iso-2022-jp-2 . 7bit)))
 
> Thanks to Yamaoka-san, It works great. *WOW*.

> # This relate to mm-bodies.el e-lisp file, doesn't this ? 
> # I couldn't find that. :-\

It is defined in mm-bodies.el, but it looks like an internal variable.
We japanese want it to be an user option and the default value is set
as follows:

(defcustom mm-body-charset-encoding-alist
  '((iso-2022-jp . 7bit) (iso-2022-jp-2 . 7bit))
  "Alist of MIME charsets to encodings.
Valid encodings are `7bit', `8bit', `quoted-printable' and `base64'."
  :type '(repeat (cons (symbol :tag "charset")
		       (choice :tag "encoding"
			       (const 7bit)
			       (const 8bit)
			       (const quoted-printable)
			       (const base64))))
  :group 'mime)

> BTW, If I'd like to read *quoted-printable* encoded e-mail messages 
> someone sent, are there any way to solve this problem (say, decode 
> messages) ?  No way ?

> Some *quoted-printable* encoded mails are sometimes sent to me. 

Eh, can't you read such messages with Gnus 5.8.4?  I can do it without
any customizing nor modifications...