The sea level in the vicinity of Kobe City was higher at the time than it is now, and the sea reached further up the Mt. Rokko area than it does today, meaning that level ground was narrow and not suitable for the movement of large armies.
当時の神戸市付近は、現在よりも海面が高かったこともあり、今以上に海が六甲山地に迫っていて平地が狭く、大軍の行動には適さなかった。