Suppose we use the "Fullwidth Hyphen-Minus" (U+FF0D) character in Shift_JIS encoding and convert it to UTF-8 in PHP.
The character will be mapped to another character, "Minus Sign" (U+2212).
$uff0d = '-';
$uff0dSjis = mb_convert_encoding($uff0d, 'SJIS', 'UTF-8');
$uff0dUtf8 = mb_convert_encoding($uff0dSjis, 'UTF-8', 'SJIS');