一夫当关，万夫莫开

Explanation: Means that high and dangerous mountains, one to the crossing, one million individuals have not come to play. Describe the terrain is very advantageous. 　　Usage: Complex sentence; as object, attribute, clause; describe the terrain is very advantageous 　　Source: "Huainanzi Binglue training" keep one narrow, but thousands of people had also Fugan. "Jin Zuo Si" Shu Du Fu, "keep one narrow, Wan Fu Mo to." 　　Examples: Jiange lofty and Cui Wei, ~. ★ Tang Li Bai "Quiet Night" Poetry Thesaurus:  bolus Scove barrier, Man guards the pass, Wanfumocui