Cai Wang Zhiji was the son of Gaozu's younger brother, Duke Zheng of Chenliu County. His father Zheng, during the reign of Emperor Ming of Zhou, was granted the title of Duke of Chenliu County due to the military achievements of Gaozu. He was later appointed as the Grand Marshal of the Palace and the Cavalry. Following Emperor Wu to fight against and pacify the Qi country, they fought all the way to Bingzhou, fighting bravely until his death. After Gaozu became Chancellor, he posthumously appointed him as the Pillar State, Grand Minister of State, and also posthumously granted him the governorship of eight states including Ji, Ding, Ying, Xiang, Huai, Wei, Zhao, and Bei. After Gaozu became emperor, he posthumously conferred upon him the title of King of Cai, with the posthumous title of King Jing. Zhiji inherited the title from his father. Gaozu also granted titles to his brothers Zhiming, Duke of Gaoyang, and Zhicai, Duke of Kaifeng. Shortly thereafter, Zhiji was appointed as the General of the Palace and also served as the governor of the same province, and the court sent a grand procession to escort him to his new post.
After a period of time, because Zhiji was prudent and had a good reputation, Gaozu appreciated him very much. He never played or hunted while serving as an official in the province. After handling government affairs, he would sit up straight and read. He never entertained private visitors at home. He had the attendant Gong Sun Shangyi, a Confucian scholar from Shandong, as well as the officials Yang Junying and Xiao Deyan in the mansion, who were all cultured individuals. Zhiji often invited them to his home, and the refreshments he offered were simple, just biscuits and fruit, and he limited himself to only three cups of wine. Although there were female entertainers at home, they played music for the Empress Dowager only during festivals and holidays. His life was so simple. When Gaozu was still a commoner, King Jing had a strained relationship with him. King Jing's Empress Wei and Empress Dugu also had a bad relationship, so Zhiji remained fearful and cautious. Gaozu knew his situation and sympathized with his plight.
Some people advised Zhi Ji to accumulate more wealth and invest in some industries. Zhi Ji replied, "Previously, the wealth of the Pingyuan family amounted to millions, but in the end, it all ended in the family's fortune being squandered. It was a hard lesson! Fortunately, I don't have much family property, so why bother to manage it?" He had five sons and allowed them to study the Analects and the Classic of Filial Piety only, without letting them interact with people outside. When asked why he did this, Zhi Ji replied, "You don't understand me." He feared that their talents might lead to disaster. In the twentieth year of the Kaihuang reign, Zhi Ji was summoned back to the capital, but he did not take on any official roles, choosing to stay at home and rarely going out except to pay respects to the emperor.
After Emperor Yang of Sui ascended the throne, Prince Teng and Prince Wei were both falsely accused and punished, and Duke Gao Yang Zhi Ming was deprived of his title due to poor relations with others, which made Zhi Ji deeply concerned. In the seventh year of the Daye reign, he was appointed as the Prefect of Hongnong, but he left all political matters to his subordinates, choosing to live a quiet life. Later, when Yang Xuangan rebelled and marched from the eastern capital towards the west, Zhi Ji told his subordinates, "Yang Xuangan has heard that the imperial army is approaching and wants to attack the Guanzhong region in the west. If he succeeds, his foundation will be secure. We should find a way to delay him and stop him from moving forward. In ten days, we will be able to capture him." When Yang Xuangan's army arrived at the city, Zhi Ji climbed the city wall and shouted insults at him. Yang Xuangan was very angry and ordered an attack on the city. The rebels set the city gates on fire, so Zhi Ji ordered the surrounding buildings to be set on fire, keeping the rebels out. After a few days, reinforcements under Yuwen Shu arrived, and together they launched an attack, defeating the rebels.
Twelve years later, Zhiji followed the emperor to Jiangdu and fell ill. Emperor Yang of Sui was cold towards his relatives at that time, which left Zhiji feeling unsettled. When he fell ill, he didn't even summon a doctor. On his deathbed, he said to his close ones, "Today I finally realize that being able to keep my head and be buried underground after death is considered fortunate." People at the time felt sorrow for him. Historical records indicate that during the Zhou Dynasty, the relatives of meritorious officials were enfeoffed as marquises, and in the Han Dynasty, meritorious officials were likened to the cornerstones of the nation, all to unify the imperial family internally and stabilize the populace externally, in order to strengthen the foundation and consolidate the position of the imperial family. In times of national stability, they can share in joy; in times of crisis, they can shoulder risks together. This practice has deep historical roots. After the Wei and Jin Dynasties, many dynasties did not adhere to this, disregarding ancestral customs and harboring personal ambitions. Suppressing them would make their power like that of ordinary people; promoting them would make their power equal to that of the emperor, which is not a problem that can be solved in a short period of time. The fortunes and misfortunes of past dynasties are documented in historical texts, so it will not be discussed in detail here. The bonds between the brothers of the Sui Dynasty's founding emperor were weak, and the conflicts in the palace were irreconcilable. When Emperor Yang of Sui ascended the throne, these issues became more pronounced. Therefore, when Prince Teng died violently, everyone discussed it privately; when Prince Cai faced death, he still regarded himself as fortunate. Only Prince Wei, who was raised by the empress dowager, received special favor, while the other princes roamed in different lands, not knowing where they would die, which was truly tragic. Though they were granted lands and referred to as the cornerstones of the nation, they lacked military protection and lived as commoners, with no internal or external security. With no hope for the future, how could they confront challenges with any optimism?
