Here it is at last, Onikakushi-hen chapter 4.
http://www.mangaupdates.com/groups.html?id=1021
Just scroll down to releases. It should be fairly straight forward from there.
All credit for the translation goes to NESS.
I'm a little curious as to why it hasn't already been posted though. The torrent
is almost a month old...
Ahhh well, such are the mysteries in life.