public static function countKanji($str, $extended = false)
    {
        $matches = array();

        if ($extended) {
            return preg_match_all(Helper::PREG_PATTERN_KANJI_EXTENDED, $str, $matches);
        } else {
            return preg_match_all(Helper::PREG_PATTERN_KANJI, $str, $matches);
        }
    }