鹬蚌相斗

Explanation: Metaphor of two sides at loggerheads, leaving from a third party benefit. 　　Source: Qing hundred lay "pot day in" the next volume to be competition between the very touch, without regard to the severity of the original, dogs fight, to damage from each other. " Thesaurus:  Two dogs locked in a stalemate, Two dogs danger, Two dogs fight