I found this at the EmacsWiki page on writing Chinese [1].

It's the work of Ye Wenbin (叶文彬), who has an Emacs wiki page [2].

The package is described in detail, in Chinese, on another EmacsWiki page,
EimForChinese [3]. Wenbin references some files from his personal home page [4]
under tsinghua.edu.cn. Unfortunately, his personal home page is no longer
present.

Unfortunately, I'm not sure where I got the tar ball any more. There is,
however, a repository [5] on github that seems to have a similar codebase.

Feel free to contact me at danking@ccs.neu.edu.


[1] http://www.emacswiki.org/emacs-zh/WritingChinese
[2] http://www.emacswiki.org/emacs-zh/Ye_Wenbin
[3] http://www.emacswiki.org/emacs-zh/EimForChinese
[4] http://learn.tsinghua.edu.cn:8080/2005211356/emacs/Eim.html
[5] https://github.com/viogus/eim