《贞观政要》载,贞观元年,谏议大夫王珪对唐太宗讲:“臣听说木材经过墨绳的测量规划,才能锯得直;国君听从采纳臣子的规谏,才会变得圣明。所以,古代圣君,必能广纳谏言。”太宗称赞王珪之言,随下诏书宣布,凡宰相入朝商讨国家大事,必须让谏官列席参加,预闻朝政,如果有所批评建议, “Zhenguan dignitaries,” set forth in the first year of Zhenguan, Wang Jian, a doctor at the proposal, told Emperor Taizong: “I heard that wood can be sawed straight through the measuring plan of the ink rope; Therefore, the ancient holy monarch, will be able to accept the advice. ”Taizong praised Wang 珪 of the words, with the next edict announced that where the prime minister entered the country to discuss the major events, we must remonstrance officials attended to participate in the pre-war government, if there are criticisms and suggestions,