牛蹄之涔

Explanation: Http: rain. Cattle hoof prints in the water. Describe the amount of water is minimal. Can also be used to make a difference in position. 　　Source: "On the training Huainanzi Bom": "Cardiff neat's foot of the http, not raw Zhan Tuna." "Huainanzi Chu true": "neat's foot of the http, no ruler of the carp." Zhou Yu "for the public Qi to master the table ":" tired of the status of a complex song, the final nine of the Taiwan crisis; an http hoof, will hurt thousands of miles of driving. "