Ouyang Xiu, a celebrated literary figure of the Northern Song Dynasty and one of the "Eight Great Prose Masters of the Tang and Song," passed the imperial examinations during the Tiansheng era and went on to hold high-ranking positions such as Vice Commissioner of the Privy Council and Assistant Chief of the Secretariat.
During the Jiayou era of Emperor Renzong's reign in the Song Dynasty, Ouyang Xiu and Han Zihua, an imperial scholar, jointly presided over the Ministry of Rites examinations. After the tests, Ouyang Xiu and Han Zihua worked tirelessly day and night grading papers. While reading, Ouyang Xiu felt as if a red-robed old man behind him was nodding in approval. Looking closely, he saw the paper in his hand was an excellent piece worthy of selection, and he couldn't help but applaud in admiration.
Strangely, as he reviewed several outstanding essays, each one seemed to have a red-robed elder nodding approvingly behind it. At first, he thought an attendant stood behind him, but when he turned to look, there was no one there.
After this happened several times, Ouyang Xiu began to doubt his own senses. To get to the bottom of the mystery, he secretly placed a bronze mirror on his desk. One day, when he found another brilliant essay and eagerly glanced into the mirror, he saw a red-robed old man nodding inside it—but when he turned around, there was no one there.
Ouyang Xiu told his fellow examiners about the scene he had witnessed, and they all marveled, suspecting that some divine force had lent a hand.
When the results were announced, literary youths like Su Shi, Su Zhe, and Zeng Gong, who later became known as the "Eight Great Masters of the Tang and Song," ranked high, adding a large number of outstanding talents to the court. Later, the idiom "Zhu Yi Dian Tou" (The Official in Red Nods) came to describe passing the imperial examination or being favored by an examiner.
Source: Chen Yaowen (Ming Dynasty), *Tianzhong Ji*
Meaning of the Idiom: Later, the Chinese idiom "朱衣点头" came to describe passing the imperial examination or being favored by an examiner.