If the Great Tang Empire Navy launches an attack on Mirage Country, the closest and most direct target would be South Island. By-passing South Island and attacking New Island would be an almost impossible task due to the high cost.
Thus, simply by guarding South Island and Ben Island, New Island, situated between them, can be considered absolutely safe. There is no need to mention Northern Island. It would be foolish for the Great Tang Empire to set out and attack Northern Island after bypassing the other three islands.
After the presentation of defense deployments by the army, Navy generals also joined the discussion. This meeting was convened due to the escalating risk of war between the Great Tang Empire and Mirage Country.