C165 Defeating enemies with grand formation

The valley was between two mountains, with hills on both sides shaped like gourds.

In the era of cold weapons, this kind of terrain could be described as deadly. As long as two of them attacked together with fire, even a million strong army would be annihilated.

Back then, the father and son pair of Sima Yi had nearly died because of Zhuge Liang obstructing their path. At the same time