Country in which there are precipitous cliffs with torrents running between, deep natural hollows, confined places, tangled thickets, quagmires and crevasses, should be left with all possible speed and not approached.
 Sun Tzu, The Art of War (5th century BC). copy citation

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Author Sun Tzu
Source The Art of War
Topic speed cliff
Date 5th century BC
Language English
Reference
Note Translated by Lionel Giles
Weblink http://www.gutenberg.org/files/17405/17405-h/17405-h.htm

Context

“Thus you will at once act for the benefit of your soldiers and utilize the natural advantages of the ground.
14. When, in consequence of heavy rains up-country, a river which you wish to ford is swollen and flecked with foam, you must wait until it subsides.
15. Country in which there are precipitous cliffs with torrents running between, deep natural hollows, confined places, tangled thickets, quagmires and crevasses, should be left with all possible speed and not approached. 16. While we keep away from such places, we should get the enemy to approach them; while we face them, we should let the enemy have them on his rear.
17. If in the neighborhood of your camp there should be any hilly country, ponds surrounded by aquatic grass, hollow basins filled with reeds, or woods with thick undergrowth, they must be carefully routed out and searched; for these are places where men in ambush or insidious spies are likely to be lurking.
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