表里山河

Explanation: Table: the internal and external. Outside the river, there are mountains. Natural barrier that has mountains and rivers as barriers. 　　Usage: Partial official; as attribute; describe the steep 　　Source: Pre Hengyu "Zuo Xi twenty-eight public": "sub guilty, saying: 'War also. Battle Jie, must princes. If it does not McNair, table mountains and rivers, will also sound.'" Du Pre-Note: "Foreign River and the mountains of Shanxi." Thesaurus:  one's outward show and inner thoughts rivers and mountains