According to the story of Jinmu tosei (a story in Japanese mythology about the first generation of the Imperial family) of Nihonshoki, the Emperor Jinmu made up his mind to go to East because Shiotsutsunooji said that there was good land in the East.
日本書紀本文の神武東征の記述では、塩筒老翁が東に良い土地があると言ったことから神武天皇は東征を決意したとある。