Wrestling Decides Imperial Succession
“In its originally modified form, wrestling is mentioned as a sacred method of deciding questions of national leadership. Mitford relates that in 858, Emperor Montoku allowed his two sons, Korehito and Koretaka, to wrestle for the throne by proxy. Champion Yoshiro, wrestling for Korehito won the crown for the latter by defeating Koretaka’s champion, Natora. Korehito subsequently became Emperor Seiwa. In the era which followed, wrestling seems to have taken two main directions. First of all, it became a form of social representation whose value as entertainment or spectacle did not obscure its intrinsically sacred character. As such, it became an integral part of festivals and other public ceremonies. Empress Kogyoku (642-45), for example, is reported to have assembled the strongest men in the kingdom to wrestle before the Korean envoy. Emperor Shomu (724-40), a famous patron of Buddhism and the builder of many temples, is reported to have also included wrestling (called sumo-no-sechie, or Wrestler’s Fete) among the traditional games and celebrations of the Harvest Thanksgiving Festival held in the month of August.” (p336)

 
Source:
Secrets of the Samurai
A Survey of the Martial Arts of Feudal Japan
Oscar Ratt & Adele Westbrook
Charles E. Tuttle Co., Inc. 10th Printing. 1987.