k, after hours of compiling and googling, i've got it to work.
To make everything in slackware japanese, edit your /etc/profile.d/lang.sh
Save, logout, and login again, and if you type locale
you'll notice its all switched to Japanese
Next, to read japanese, you need a font, i used msgothic.ttc which is a japanese font.
copy it to
cp msgothic.ttc /usr/X11R6/lib/fonts/TTF/
To allow OpenOffice to read (and later, write) japanese, copy the font to
cp msgothic.ttc /opt/openoffice.org1.9.79/share/fonts/truetype/
This will also allow perfect reading (and later, writing) in gaim, firefox, etc...
Next, you need a program to let you write japanese. There are two, and a library.
scim 1.2.1 (the one i use)
uim 0.4.6 (i dont use, but i installed it anyway)
anthy 6300 (the library, install that too)
scim-uim 0.1.3 (dont know if you need it or not, but i installed anyway)
skim you don't need, and scim-anthy refused to compile.. but ignore them for now.
When installed, just open console and type
and it will open in the taskbar. If you view the setting you should be able to see 'English/keyboard' and 'Japanese anthy'. The latter is what you need.
Now, open whatever app you want (firefox, soffice, ), and hit CTRL + SPACE
to switch between languages, and you should be able to write in Japanese.
note: for openoffice, you need to select the font from the tab first.
This should do the trick. And i hope this helps anyone.
Note: To write in Japanese in Abiword, msgothic.ttc won't do the trick. You need the kochi-gothic and kochi-mincho fonts.