The one kanji character of Yasutane HORIKAWA's name, 'yasu' (康), was a gift from Ieyasu TOKUGAWA (徳川家康), Yasutane became Jikkonshu (the family on friendly terms) of the Edo bakufu (Japanese feudal government headed by a shogun), and later, he was promoted to Chunagon (middle counselor).
康胤は徳川家康から一字を与えられて江戸幕府昵懇衆となり、後には中納言に昇った。