Thanks for all the help on this one everyone. I ended up using Encode to decode the shiftjis text, and used an exclusion list made up of characters I don't want to see in the final output, and finally compiled this list into a traditional:

my $string = "NON_DELIMITED_CHAR_LIST";
my $regex = qr/
s/[^a-z]//g;
[download]

type of structure. This worked as expected, but still seems a little bit more messy than it ought to need to be. I'd still prefer not to have the big long list of characters. Anyway, thanks!