踏破铁鞋

Explanation: Compared to going through something difficult to find, takes great effort. 　　Usage: Verb-object type; as predicate, object; refers to the cost of great effort 　　Source: Ming Feng Meng "Jingshitongyan": "It is: wear out iron shoes in hunting, must come to not a waste of effort!" 　　Examples: Cao Jinghua, "sighed old wooden bridge _set_ of the first fly hovering no final": "all kinds of books, YAM rather than a rush, ~, are not properly resolved."