noun
physically exceptional wrestler promoted straight to ōzeki during the Edo period
Historical sumo term. Refers to a wrestler of outstanding physique who was granted the second-highest rank of ōzeki without the usual promotion process, a practice specific to the Edo period.
江戸時代には、看板大関としてすぐに大関に昇進する力士がいた。
In the Edo period, there were wrestlers who were promoted straight to ōzeki as kanban-ōzeki.
Ōzeki is the second-highest rank in sumo; 看板大関 is a historical special case of promotion to that rank.
Compound of 看板 (kanban, 'signboard' or 'poster') and 大関 (ōzeki, the second-highest sumo rank). The term likely originates from the practice of using such wrestlers as 'poster boys' to attract spectators.