There comes a time in the game where we are ruling our settlements peacefully and this a**hole of an AI gets a de jure, fabricated or Holy War claim over one of your counties/dukedoms. Normally, this happens when the AI senses that it can beat you because it thinks it has a better army than yours, and when this happens you can either fight the AI or you can hire mercenaries to help you out.

However, what if the stacks are against you? like the troop ration is 2:1 or bigger? and you don't have the money to hire the mercenaries. Then the only thing you could do is to actually surrender BACKDOOR your opponent.

PS: Backdoor in layman's terms means "to bypass", technically this guide will be showing you a way of bypassing your opponent.

Back in CK2, when you engage in a battle using your leader and he/she gets caught, the war would be over and you would lose the war. Now this time in CK3 it's almost the same but this time it works both ways, like if you don't command your army (meaning you would stay at your capital) and the AI actually sacks your capital then there is a chance you would lose the war since there's a big chance that you will be caught in the sacking.

I accidentally discovered this when I wanted to kick out one of my vassals in North Africa. I was the Queen of Sardinia and I sent an army with lead by my counselor to the Constantine County to kick him (the AI) out. Apparently, the AI avoided my army and instead went for my capital and when I attempted to get back, my capital was already sacked and guess what; I (my character) was in it. Basically, I discovered this game mechanic because the AI BACKDOORED me.....

Well anyway, fast forward to a couple generations and I was mostly at peace in the mediterranean and through the years I was able to get a county in Hispania. Then out of nowhere, the Idrisid sultan wanted to take my sole county in Hispania. During that time, I only had 1600 soldiers and the Idrisid sultan had around 4600 so basically the odds were 4-1 against me. I first thought of surrendering since the county is isolated anyway, but then I remembered what happened with my stupid vassal in North Africa and I was like, I'm gonna lose the county anyway so I mind as well do that YOLO move the AI had "taught" me.

So what I did was like this:
Instead of engaging the Sultan/AI's army (which is kind of stupid) or surrendering immediately, I went for his capital. I sent all of my troops to his capital as soon as they gathered while he sent his entire 4000 man army to the small county in Hispania. I was able to get to his capital first while his army was still disembarking at Hispania, and that gave me enough margin of time to sack his capital. And guess what? when I sacked his capital, HE WAS THERE and the war score suddenly turned 100% for me. I was ecstatic.

IMPORTANT; Speed is the key in this strategy, you must avoid any battles and other non-sense so that you could get to the enemy's capital in the quickest way possible. If you're too slow and the AI takes your county first then you're screwed.

Well let's say you sacked the enemy capital and somehow the enemy liege was not there or the enemy liege was actually leading the armies. Well most probably you would still get something in return, because in the sacking you would most probably get a close family member for ransom and it raises your war score perhaps to a point where it should be enough for you to earn a white peace.

Now let's say you say you got this possible worst case scenario, you sacked the enemy's capital but you didn't catch the enemy liege, you got his/her close family members but the war score wasn't enough for a white peace or you were too slow that your own county got sacked first. The last thing you could do is actually "kill" the family members. It may sounds so morbid (it's just a game) but if you manage to catch the heir, spouse, relatives you mind as well kill them. If you kill them you would destabilize the hierarchy of their kingdom, and if it gets worse it will disintegrate the kingdom and thus its counties would be easy pickings for you in the future. Think of it as a "middle finger sign" to the AI for taking your county.

Generally no. Because let's say you have to attack the county but you want to avoid the enemy, apparently it's not possible because the enemy will just be there waiting for you.

However, I manage to use this trick offensively in the crusades. The Crusade was in England and the war was about to hit the 10 year mark with no end in sight (the war score was negative for us Crusaders but it couldn't go higher than -70 and it comes down back to -30 at some point) after noticing the length of the war I decided to do this trick to the enemies of the Crusade. Since most of them are in Scandinavia, I went for their capitals and I sacked them. This doesn't help the Crusade score since I did not take the crusade county states but on the long haul this trick helped the Crusade, with their capitals sacked, they had to send fewer reinforcements and it eventually killed them in the Crusade.