During the Kamakura Period, when there were many wars raging, like the Jokyu no ran and Bunei-Koan no eki, they provide many opportunities for samurai to prove themselves in battle.
承久の乱や文永・弘安の役などの戦が増えた鎌倉時代には、武勲を上げる武士にとって絶好の機会が増えた。