The Three Kingdoms era was divided into the Three Kingdoms in the broad sense and the Three Kingdoms in the narrow sense, the Three Kingdoms in the broad sense began in 184 AD to the end of the Jin Dynasty in 280 AD, and the Three Kingdoms in the narrow sense began in 220 AD from Cao Pi's usurpation of the Han Dynasty to 280 AD. The difference between the two is that in a broad sense, the actual control of the Eastern Han regime is said to be the actual control of the Eastern Han Dynasty, after the Yellow Turban Uprising, the Eastern Han regime has been unable to control the local political power, the local forces have risen and do not listen to the central dispatch, the Eastern Han Court exists in name only; the narrow sense is that the Existence of the Eastern Han Dynasty, although it is said that the masses are together, but the world is still the Great Han World, the national name is still Han, until 220 Cao Pi usurped Han is the real demise.
The overlap and space of dynasties in the three kingdoms, for example, the three kingdoms of Shu, Wei and Wu were indeed not formed in the same year, and the State of Wu was still there when the Western Jin Dynasty was founded. Therefore, the official statement about the han dynasty after the fall of the Han Dynasty is the Wei and Jin dynasties, because such a timeline is coherent. The beginning of the Three Kingdoms, in fact, just like the Five Dynasties and Ten Kingdoms at the end of the Tang Dynasty, is not divided according to when those divided countries were established, but according to when the previous dynasty collapsed, the Eastern Han Dynasty perished in 220 years, thus opening the next dynasty, in order to avoid the historical vacuum period, there is a Wei and Jin Southern and Northern Dynasties, of course, there are also three kingdoms and two Jin Southern and Northern Dynasties, but more exist in the folk.
The Three Kingdoms period in the modern historical sense refers specifically to the aftermath of the Han Dynasty, but there are reasons for folk works such as the Romance of the Three Kingdoms and the Commentary on the Three Kingdoms, and the Broad Sense of the Three Kingdoms also has the saying that it began with the Yellow Turban Rebellion. Cao Cao did become the King of Wei before his death, but nominally he was still a courtier of the Han Emperor, and it cannot be said that cao Cao wrote the Three Kingdoms Chronicle and said that he was a native of the Three Kingdoms, because Sima Zhao also achieved the King of Jin before his death, but at that time, the Wei Emperor Cao Zhao was still reigning, and the Book of Jin also wrote about Sima Zhao, was Sima Zhao also a Jin Dynasty person? If it is a kind of history, the situation to be put on the table is to talk about the Three Kingdoms in a narrow sense, so there is no big problem that Cao Cao is not a figure of the Three Kingdoms.
History is complex, not all dynasties are based on the demise of the previous dynasty, and there is often overlap in time between successive dynasties. Later historians generally choose the establishment of the so-called orthodox dynasty to divide the era, which is not clear but is widely recognized. The State of Wei is considered by Chen Shou to be the orthodox continuation of the Han Dynasty, so the Three Kingdoms refers to the fact that since Cao Pi was proclaimed emperor, Cao Cao was recorded because he was posthumously awarded the Title of Emperor of Wei, so it is counted in the Chronicle of the Three Kingdoms. By the time of Cao Cao's death, the world still boasted that the people of the Han Dynasty did not exist in the Three Kingdoms, so it should refer to "people who did not live in the Three Kingdoms period" here. In fact, there is a similar problem in replacing Cao Cao with Guan Yu here, they all belonged to the Han Dynasty before they died, but they can also belong to the Three Kingdoms after they die.
From the perspective of strict legal system, even if the king does not destroy the legal system, even if it has the essence of the uncrowned emperor, it still belongs to the Eastern Han Dynasty in name. The reason why Cao Pi was chosen to call the emperor a node is only because at the same time that Cao Pi forced the Han To offer the emperor the throne, the legal system of the Eastern Han Dynasty no longer existed, which was the starting point of the Three Kingdoms in legal system. As for the "Romance of the Three Kingdoms", I personally believe that no era is divided, and the normal quotation in the history book tracing the ancestral inheritance relationship is to tell the elements of the rise of an era, and does not mean that the recognition of this process belongs to the legal system established later, such as the life of Xiang Yu, which must be written in the history of Han, does Xiang Yu belong to the Western Han Dynasty?
Speaking of the Eastern Han Dynasty, in 220 AD, Emperor Xiandi of Han was forced to sit in Cao Pi, a year that is seen as the end of the Eastern Han Dynasty and the beginning of the Three Kingdoms. In 280 AD, Eastern Wu fell, and the Western Jin Dynasty officially unified the country, a year that is considered the end of the Three Kingdoms. For most of this 60-year period, three countries coexisted, but not always three countries.
Whether Cao Cao was a loyal vassal or a traitor is still inconclusive, and wu and Shu said that Cao Cao blackmailed tianzi to order the princes, and he was a traitor who coerced the emperor. Cao Cao, on the other hand, compared himself to the Duke of Zhou, ruled on behalf of the emperor like the Duke of Zhou and was a loyal vassal through and through. If Cao Cao was allowed to evaluate himself, he would definitely put himself on the Eastern Han Dynasty figures.