Question: What does "important land" mean in slogans such as "An important production place, idlers are not allowed to enter", "An important military place, idlers are not allowed to enter" and other

Question: What does "important land" mean in slogans such as "An important production place, idlers are not allowed to enter", "An important military place, idlers are not allowed to enter" and other slogans? Where does it come from?

The "important areas" in slogans such as "In important production areas, idlers are not allowed to enter", "In important military areas, idlers are not allowed to enter" and other slogans, the "important areas" come from the Nine Places Chapter of "The Art of War" by Sun Tzu: Sun Tzu said: The method of using war has scattered areas. , there are light places, contested places, intercourse places, thoroughfares, important places, dilapidated places, enclosed places, and dead places. The princes fought against each other and their lands were scattered. The place where people enter is not deep, it is a light place. If I get it, I will benefit, and Peter will also benefit, in order to compete for land. Where I can go and he can come, this is the place of friendship. Among the three tributaries of the land of the princes, the one who comes first and conquers all the people in the world is called the Qu land. If the land is deep and has many cities and towns behind it, it is an important place. When traveling through mountains and forests, there are dangers, obstacles, and swamps. Any path that is difficult to walk is a ruined land. The place we enter through is narrow, the place we return from is roundabout, and those few people can attack our army, this is the encirclement. If you fight quickly, you will survive; if you do not fight quickly, you will die. This is the place of death. Therefore, if the ground is scattered, there will be no fighting; if the ground is light, there will be no stopping; if the ground is contested, there will be no attack; if the ground is intertwined, there will be no end; if the ground is narrow, it will be joined; if the ground is heavy, it will be plundered; if the ground is ruined, it will be marched; if the ground is encircled, there will be plotting; if the ground is dead, then there will be war.

Please note: if the land is deep and has many cities behind it, it is an important land. The important land will be plundered. The original meaning is that a lone army has advanced into the enemy's heartland, with no rear and no supplies, which means that there is no guarantee for the safety and survival of the army.