currently groff-1.1.19 not support cjk & man-pages-ja. I found CJK patch for newer 1.18.1.1 from debian-jp and wrote new ebuild Reproducible: Always Steps to Reproduce: 1. 2. 3.
Created attachment 70992 [details] groff-1.18.1.1.ebuild newest CJK support groff
Created attachment 70993 [details, diff] groff_1.18.1.1-10-fix.patch
base system does not support groff-1.18.x ... only reason it's still in the tree is for cjk users
Thanks for the patch. I've added it to CVS.