Hello!
Quick background, I'm writing my MA thesis right now on the subject of the Three Kingdoms in the historical aspect. As such, besides sources such as Rafe de Crespigny's works, I had to delve deep into sources written in Chinese, and, of course, Sanguozhi and the annotations by Pei Songzhi. I'm not an expert when it comes to classcal Chinese, but I can read it to some degree and spent a fair amount of time researching the chapters that I wanted to use.
Now here's a problem I faced: My thesis supervisor argues that neither 三国志 nor 三国志注 can be treated as historical sources and that they are highly fictional, which left me flabbergasted. While I do know that modern historians argue over whether or not Chen Shou was biased in his biographies and I know that Pei Songzhi himself disputed some of the stories he annotated, I always considered Sanguozhi as the key historical source to the events that happened during the Three Kingdoms period.
So here's my question: Am I right or is my supervisor right? If I'm right, how to prove it? Are there any reputable sources, especially in Chinese, that I could use to prove I'm right? If I'm wrong, what other sources could I use?
To clarify: I mostly used Sanguozhi and the annotations when writing about Lü Bu, Guan Yu, Zhuge Liang and Sima Yi.
Thank you for your input!