Why are free cards useful? A look at a passage in Sun Tzu's Art of War will enlighten you.
Therefore, the upper soldiers cut the plot, the second cut the friendship, the second cut the soldiers, and the next attacked the city. The method of siege is a last resort. Repair the temperature of the bridge, with equipment, three months and then complete; from the valley, and three months and then has. They will be overwhelmed by their wrath and will be possessed by ants, and kill one-third of the soldiers, and those who do not pull out the city will also be the disaster of this attack. Therefore, those who make good use of soldiers, the soldiers who bend the people instead of the war, the city that pulls out the people instead of the attack, and the country that destroys the people instead of the long time, will fight for the whole world, so the soldiers will not be able to profit, and this method of attack is also the same.
Simply put, wars under unequal conditions often cost one side a lot, so try to avoid them. This is a prerequisite for the free card to work.
In ancient wars, the consumption of their own troops was very important, the generals were also people, every soldier was a living life, less than the last resort, no one would ignore the value of life, so every time the war was launched, it was carefully considered, repeatedly deduced, and tried to minimize casualties. The kind of general who relies entirely on flesh and blood, whose head is hot and does not care about the casualties of soldiers, and who uses life pads, there are many in TV dramas, and there are not many in history. And it is difficult for such a general to grow into a senior general.
The two armies were opposed, and the defensive side with fortifications had an absolute advantage, especially the city. Therefore, in ancient battles, we will try to fight in the case of equal conditions between the two sides, and if possible, try to avoid taking the initiative to attack the defensive side with defensive fortifications. The battle-free card will only be useful if there is a city or a fortification, otherwise the other party will not care whether you are hanging up the battle card or not, and will fight according to its own combat intentions.
In the novel, it is often seen that the siege side generally does not directly attack the city, but surrounds it, and then scolds the enemy and stimulates the other party to go out of the city to fight. The reason is very simple, the loss of the strong attack is too large, there are no casualties of more than five times, it is difficult to break through the city, and only when there is really no way to take the city will it be attacked. The best way is to besiege, cut off their supply of grain and grass, and force the other side to go out of the city to meet the battle, so that the other side can be pulled to the same conditions as themselves, and the loss is minimal. But the defending side will certainly not easily go out of the city to fight, and hanging up the battle card is equivalent to telling the other side, we do not go out to fight in the city, do you have the ability to attack the city? However, a besieged city generally does not last too long, the consumption of the whole city's military and civilians is not a small number, it is impossible to hold on for a long time, and it is generally a one-sided enemy to be supplied. The defensive advantage of the city, if faced with food and water, sometimes had to go out of the city to fight.
Even if there is no city, a truly strategic attack, before the two armies are opposed, will generally set up camp and set up temporary fortifications, although not as strong as the city, but relying on these temporary fortifications will still bring great trouble to the attacking side. Therefore, there is no great necessity, no one will storm the camp, generally agree on the time and place, set up a position, and the two sides will go to war. If one of the sides does not want to go to war immediately, it will close its doors and rely on the advantage of defensive fortifications, and when the war starts, the other side will pay a heavier price to achieve victory. Without a strength advantage, it is difficult for the active attacking side to achieve results. There is no need, no one goes back to fighting this kind of asymmetrical war. At this time, the defender hung up the free battle card and could not get out of the wall. The attacking party will generally only insult the other side outside, provoking the other party to line up to fight, and will not easily launch an attack.
The free battle card is actually a defensive advantage that the side tells the other side, I will not come out of the wall, and you have the ability to attack. In the encounter on the way to the march, there will be no such thing as a free battle card, and when there is no condition to limit the opponent's active attack, the free battle card has no effect.
The so-called impermanence of soldiers, water impermanence. Because of the complexity of the war situation, sometimes you have to pay a greater price to attack, and at that time, the free battle card is nothing, and it breaks a piece of wood. Therefore, the free card needs a lot of favorable factors to support it under certain conditions, and it will be ignored more often.