i think i found a solution for the java game. in the home dir, put a .profile to read .bashrc file
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
in the ~/.bashrc file, put a line to read /etc/bashrc
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
and in the /etc/bashrc, put the lines
export LC_ALL=zh_TW.Big5
export LC_LANG=zh_TW.Big5
export LC_CTYPE=zh_TW.Big5
ofcause, you need to emerge the chinese fonts (edit /etc/X11/fs/config), and java games should show the correct chinese characters.
next, i will try to install xcin and wish myself good luck.