Personally, the reasons why Wang Ping abandoned the powerful Cao Cao and voted for the weak Liu Bei are analyzed as follows from The History of the Three Kingdoms and The Romance of the Three Kingdoms. In the Romance of the Three Kingdoms, Wang Ping handed Cao to Liu and put the blame on him.
History of Three Kingdoms
According to the Records of the Three Kingdoms, Wang Ping, Zi Zijun, was born in Dangqu, Bacilly (now the northeast of Quxian County, Sichuan Province). When I was a child, I grew up with my grandparents, so I was also called He Ping. In September of AD 2 15, Zhang He moved seven people, including Pu Hu, from Brazil County to Luoyang, in which Wang Ping was the team leader. So he just started as a soldier, but under Cao Cao.
In AD 2 19, veteran Huang Zhong beheaded in Dingjun Mountain Array in the summer, and Cao Jun was leaderless. Cao Cao had to lead an army to support Hanzhong front. At this time, Wang Ping was among them. The biography of the Three Kingdoms Wang Ping is recorded as follows: He was a pseudo-captain in Luoyang with Du Fu and Park Huyi.
However, in the battle of Hanzhong, Cao Cao's general Xia was killed. Cao Cao is old, his morale is low, and everyone has no confidence in regaining Hanzhong. On the other hand, Xia, the general who killed the enemy around Liu Bei, has high morale. Everyone is full of confidence in this war. They think that Cao Cao is not as powerful as he imagined, nor is he invincible, and he has no fear of Cao Cao. Hanzhong is the gateway to Yizhou. "Without Hanzhong, there would be no Shu State." Liu Bei will win Hanzhong as long as he works hard.
Hanzhong is a "chicken rib" compared with Cao Cao. Unfortunately, it tastes tasteless. After the bitter struggle, give up Hanzhong and retreat to Chang 'an. In the end, after Liu Bei did his best in the whole country, he finally won and completely occupied Hanzhong.
In this battle, Cao Cao was defeated, and Wang Ping may be captured by Liu Bei, who was originally from Brazil and surrendered to Liu Bei. Liu Bei is the land of employing people and readily accepts the obedience of Yizhou locals. From then on, Wang Ping became a general, followed Zhuge Liang to attack Wei many times and made great achievements. Especially after Zhuge Liang died in Wuzhangyuan and Wei Yan was killed, Wang Ping guarded Hanzhong, continuing Wei Yan's "heavy door strategy". In 244 AD, Wang Ping repelled the hundred thousand troops of Cao Wei general Cao Shuang in Hanzhong with less than thirty thousand troops, which was impressive.
Romance of the Three Kingdoms
In Romance, after Zhao Yun's Hanshui River was beheaded in the summer, Cao Cao led the army to March by road and seize Hanshui River. So he made Wang Ping, who is familiar with Yizhou geography, a pioneer and reached Hanshui River. The two men argued endlessly about whether to cross the Hanshui River to camp. Huang Xu wanted to cross the Hanshui River, emulate Han Xin's "last battle" and defeat Zhao Yun and Huang Zhong's army in World War I, but Wang Ping thought it was wrong. If the army needs to retreat, it is difficult to cross such a narrow bridge urgently.
Unfortunately, the officer was killed by Yipin, and Wang Ping persuaded him many times, to no avail, similar to the situation that Wang Ping persuaded the coach Ma Su in the street pavilion later. Wang Ping was proved to be correct. He was a lieutenant, but the main commanders, Huang Xu and Masu, failed to follow his correct advice and suffered a crushing defeat. Sure enough, as Wang Ping expected, Huang Xu was ambushed by Zhao Yun and Huang Zhong and was defeated. He "fought to the death" and returned to the camp, blaming Wang Ping: "You see our army is in danger, why not save it?" Wang Ping also plausibly retorted that if he went to save Huang Xu, Dazhai would fall. I once advised you not to go, but you wouldn't listen to me. Who is to blame for this fiasco?
Huang Xu was furious and wanted to kill Wang Ping. Wang Ping was very angry, but he took his troops and set a fire that night. He took advantage of the chaos to escape, crossed the Hanshui River and defected to Zhao Yun. Later, he met the master Liu Bei and said that he was very familiar with the geography of Hanshui River. Liu Bei was overjoyed and thought, "If you win the vassal state alone, you will undoubtedly win Hanzhong." He appointed Wang Ping as a partial general and led the township ambassador.
As can be seen from the above description, Wang Ping was suppressed by Huang Xu, the general, and repeatedly remonstrated and refused to listen. Finally, Huang Xu shirked his fiasco to Wang Ping and tried to kill Wang Ping. Huang Xu fled back to see Cao Cao, Master. He just said that Wang Ping rebelled and surrendered to Liu Bei, without mentioning his own fault. Wang Ping had no choice but to abandon Cao for Liu and Cao for Liu. In The Romance of Wang Ping, Wang Ping was responsible for abandoning Cao for Liu, which was somewhat "framed" and "blamed".
Summary: Wang Ping was originally from Yizhou, and went to Luoyang to become a subordinate of Cao Cao, whether it was the romance of the Three Kingdoms or the Three Kingdoms. The difference is that in the "Three Kingdoms", he was defeated and surrendered to Liu Bei, while in the "Romance", he was excluded and had to abandon Cao to Liu. Wang Ping is a great general. He has rich combat experience and is familiar with geography. He is everywhere.