This tradition, if it is indeed a tradition, is not that ancient, seemingly established only in the modern period. All Tatsunami-Isegahama yokozuna only since Yoshibayama (43rd, 5 after Terukuni) have performed Shiranui. Nishonoseki is also the other major contributor of Shiranui yokozuna in the modern period (Tamanoumi, Takanosato, Kotozakura, and Wakanohana III), although they do have yokozuna who did Unryu. Before Terukuni, only Tachiyama (22nd, Tomozuna) performed Shiranui; Otori (Miyagino) and Onishiki (Asahiyama) did Unryu. The above assumes that no elder names (or at least stables) have jumped ichimon - which is probably not justified and a major source of error.