Wnn4.2 is a Japanese/Chinese/Korean input method.  
This is the Japanese version.

This is originally based on the FreeBSD port, with contributions by

Satoshi (asami@cs.berkeley.edu)
Hidekazu Kuroki (hidekazu@cs.titech.ac.jp)
Yoshio KATAYAMA <kate@pfu.co.jp> 
S. Taoka <taoka@infonets.hiroshima-u.ac.jp>

The OpenBSD port separates the dictionaries into a separate package
(ja-Wnn-dict-4.2) that installs under /var/dict.