mountain castle
「山城」 has another reading with different meanings.
廃墟となった山城が観光地として整備された。
The ruins of a mountain castle were developed into a tourist site.
険しい山城に攻め込むのは容易ではなかった。
Storming a mountain castle built on steep terrain was no easy feat.
この山城は戦国時代に築かれ、数々の攻防戦の舞台となった。
This mountain castle was built in the Warring States period and was the site of many battles.