Another rule was "White and glossy stones of Kishu origin cannot be used by officials of Sixth Rank or lower, who should use black lacquered rhinoceros horn", (one theory claims they were often lacquered).
紀州産の石の白く艶のあるものは六位以下には使えない、六位以下は漆で黒く塗った（単に黒い色の犀角とする説も有る）犀角（烏犀/うさい）を使う。