In this paper, I tried to take a step closer to the mentality of medieval warriors by examining the mysterious phenomena that appeared during the battles of the Kamakura period. Specifically, the discussion was focused on the aspect of the relationship between the nature of the battles and the mysterious phenomena, and the formation of the ancient practices of Togoku (東國). The Kamakura samurai maintained the perception that mysterious phenomena appeared differently depending on the nature of the battles. Kamakura Bakufu became the driving force to move the mystery of Togoku from the oral world to the world of record. Togoku’s own ancient practices on mysterious phenomena was formed from the memory on the Battle of Oshu (奧州), which confirmed the identity of the Kamakura Bakufu.