Vantage Japanese language facilities support ISO 8859-15 (Latin9) with the restriction that the code points 80-85 and the LETTER Z WITH CARON are not allowed.
The characters at 80-85 are in the C1 control region and are not considered to be essential. The character LETTER Z WITH CARON is part of the support for Finnish, but is not considered part of the Finnish alphabet and is rarely used even in Finland.