The article discusses the highest rank among the five noble titles in Japan, the Duke (公爵), established by the 1889 Peerage Law, which allowed Dukes to automatically become lifetime members of the House of Peers upon reaching 30. Dukes received a family endowment to maintain their status. The Duke title was conferred upon four main groups: the Imperial Family, noble families (notably the five regent families), samurai (only the Tokugawa family), and meritorious individuals who were elevated due to their achievements. The article also explains the second rank, Marquis (侯爵), which similarly allowed lifetime membership in the House of Peers but without financial support. The Marquis title was granted to various families, including those of notable figures from the Meiji Restoration. The third rank, Count (伯爵), required election among peers for House membership, and the article outlines the families eligible for this title. The fourth rank, Viscount (子爵), also required election and notably did not include the Imperial Family. Finally, the lowest rank, Baron (男爵), is briefly mentioned, indicating that descendants of Southern Dynasty warriors were also recognized.