璧是古代贵重的瑞玉。它和圭、璋合称三玉,远在夏商时期,就作为礼器使用了。凡是诸侯贵族朝聘、会盟和祭祀的时候,都要持之以表礼仪。据说,禹曾经在涂山会合诸侯,“执玉帛者万国”(《左传·哀公七年》)。当时诸侯所执的玉,即是圭、璋、璧之类。到了春秋战国,这套礼节和制度更加盛行。国家之间的国事访问往往要用璧作为凭信,即所谓“问士(通事)以璧”(《荀子·大略》)。秦 Bi is the ancient precious Ruiyu. It and Gui, Zhang collectively Sanyu, far in the Xia and Shang dynasties, as a ceremonial use. All nobility aristocrats to hire, League and sacrifice, we must hold the table etiquette. It is said that Yu once held a meeting in Tunsan princes, “all nations” (“Zuo elders” for seven years). At the time of the princes jade, that is, Kyu, Zhang, Bi and the like. To the Spring and Autumn and Warring States, this etiquette and system more prevalent. State visits between countries often use bi as a signal, that is, the so-called “questionor (General)” (Xunzi). Qin