What does Zhao Kuo mean by an armchair strategist?

During the Warring States Period, Zhao She, a general of the State of Zhao, defeated the invading Qin Jun and was promoted to Qing Dynasty by King Huiwen of Zhao.

He has a son named Zhao Kuo, who has been familiar with the art of war since childhood and loves to talk about military affairs. People often say that he is not. So I am proud and think the world is invincible. However, Zhao She was very worried about him, thinking that he was just an armchair strategist, and said, "In the future, Zhao doesn't need him as a general. If you use him as a general, Zhao Jun will be defeated. "

Sure enough, in 259 BC, when he attacked again, Zhao insisted on resisting the enemy in Changping (now near Gaoping, Shaanxi Province). Zhao was already dead at that time. Lian Po is in charge of commanding the whole army. Although he is old, he still has a good way of fighting, which makes Qin Jun unable to win.

Knowing that it was not good for him to drag on, the State of Qin used double agents to send people to Zhao to spread the news of "General Zhao Kuo, the son of Zhao She, which Qin Jun was most afraid of". The prince of Zhao was cheated and sent Zhao Kuo instead of Lian Po.

Zhao Kuo thought he was good at fighting, and moved all the articles in Sun Tzu's Art of War to the dead. After Changping, he completely changed Lian Po's battle plan. As a result, more than 400,000 Zhao troops were wiped out, and he himself was shot by Qin Jun.

On paper, empty talk can't solve practical problems. It is also a metaphor that empty talk cannot become a reality.

Extended data;

Query on idioms

There was no paper in the Warring States period, and paper was not widely used in historical records. Obviously, this idiom could not have been written during the Warring States period, nor could it have been written by Sima Qian.

The embryonic form of an armchair strategist appeared in the Tang and Song Dynasties, and was first used as an idiom in the Qing Dynasty, but it all refers to the scholar's use of troops, and has nothing to do with Zhao Kuo. There is not even such a statement in the Chronicle of the Eastern Zhou Dynasty.

The earliest record of Zhao Kuo's so-called armchair strategist should be "Zhao Kuo's armchair strategist" in the 40th quarter of five thousand years. This is to evaluate whether Zhao Kuo is an armchair strategist, but obviously it can't be said that this idiom originated from Zhao Kuo.

As for the invention of this view, it is probably the credit of Modern Chinese Dictionary, which clearly defines the origin of this idiom in the battle of Changping, probably based on five thousand years.