古代帝王賜給功臣享有世襲爵位和免罪等特權的證件時，宰白馬歃其血，以示堅守誓約，後人稱為“丹書白馬” Emperors of the hereditary title of nobility given to meritorious and impunity enjoyed special privileges such documents, the slaughter horse drink his blood, to show stick to their vows, later known as the "Dan White Horse Book"