居庸关
In the next year, he was given command of the troops in Jizhou to defend against the Mongols. Qi oversaw the repair work on the segment of the Great Wall between Shanhai Pass and Juyong Pass. He also directed the construction of watchtowers along the wall. After two years of hard work, more than 1,000 watchtowers were completed, giving the defensive capability in the north a great boost.