Tángdài hěnduō shīrén xiě guo sàiwài de fēngshā hé zhànzhēng.
Many Tang poets wrote about the wind-blown sand and the wars beyond the Great Wall.
Tips
usage
塞 is a fortified frontier pass. 塞外, like 塞北, means the steppe north of the Great Wall, the opposite of 关内 (inside the passes) and 中原 (the Central Plain). Tang 边塞诗 (frontier poetry) made it the land of wind, sand and homesick soldiers.
mistakes
塞 has three readings: sài in frontier words like 塞外, sāi for "to stuff" as in 塞车 (traffic jam), and sè in written words like 堵塞 (blocked).