It is more logical to explain the battle assuming the location was the cliff of Tekkai-san Mountain, which is located on the rear side of Ichinotani, than assuming it was Hiyodorigoe, which is located a greater distance from the Ichinotani region.
一ノ谷から遥かに離れた鵯越より、一ノ谷背後の鉄拐山の崖である方が戦況の説明が合理的になる。