This strategy does not work well in EU3/IN 3.1, since every diplomatic annexation forces a one point move toward decentralization and it is no longer possible to vassalize large countries, either diplomatically or militarily. This was changed in HTTT where instead Stability is reduced by 1. Furthermore the addition of the Sphere of Influence allows diplo-annexing by almost anyone.
Within Divine Wind it is remarkably easy to successfully DA AI nations with suitable preparation. You need to have a high Diplomacy ruler and lots of Prestige. The method is bullet pointed in three steps below.
- Use your Prestige to expand your sphere of influence over everyone you can, friends, enemies, vassls, especially OPMs. Each country in your SOI gives a +1 diplomacy bonus, having 10 countries is now better than the most silver tongued of rules. You should aim to have a DIP skill somewhere in the region of 30
- Make friends with your desired targets for annexion, you can DA up to five if you have good relations with each and send all diplomats on the same day, make sure you have enough diplomats if trying this, this also minimises the number of stability hits
- Repair relations with other vassals and burn Infamy using your high diplomacy ruler.
Badboy Wars Tactic
This is a tactic which only works for the original EU3. It should only be attempted if you already have several large vassals who are your allies, large armies, and very full coffers. It will give you a DoW from every other nation that would ever dream of attacking you. That may seem bad right? Wrong. Because you have the armies and the funds to make your dream of world hegemony a reality, without the stability hits that you would otherwise take.
A variation on this strategy doesn't use Diplo-annex to get the badboy points but uses Turbo-annex. The benefit over Diplo-annexing is that it is a lot faster and you gain more BBs by it too, making it much more likely for everyone to declare war on you.
In the Beginning....
Gain two powerful states as your allies and several large vassals. This is the hard part of this plan but after this is complete you will be almost ready for your war. Keep an eye out for the lucky nations. These should be large powers like the Ottomans, French, Austrians, Spanish, Germans, Burgundians, Russians, or anyone else who rose to prominence through the vagaries of history. This can be achieved by winning a war and settling for vassalization, then ask for an alliance. An alternative to this conquest is to diplo-vassalize these nations, but that requires patience.
The 10 year lull
Prepare your economy to lose all of its trade because of the BBs which will be accrued by this action. Build up the largest military you can, filling your coffers with about 2000 ducats(you will need it), and enlarging your manpower pool. When you feel that you could win victories against 2/3 of your foes, diplo-annex the vassal in your religion with enough provinces to make your Badboys go above 30. The higher above 30 they are the more likely the nations around you will declare war on you. It takes 10 years to Diplo-annex. During that time you can do other things that raise your BBs almost to 30. This ensures that the surge of BBs after the diplo-annex is a sure way of getting everyone except your allies to declare war on you. This means you want your vassals allied to you, too.
War to end all Wars
Now the largest war you have ever seen will start. Everyone will try to attack you, but you and your enormous military and full coffers will be more than a match for their attempts to invade you. Use Hitler's example and surge across the borders of your foes one at a time, forcing vassalization or large concessions from the treaties. After you win, you will have about 5 years to prepare to steamroll them again as they will try to rise up if you do not ally them through gift spamming. Soon, all of Europe will bow before your will and you will be free to expand as you see fit.
During this time you will ally your vassals, tying them to your empire and giving you a vast reserve of manpower to aid you as you push across Eurasia to China and in the New World to assist in colonization. You will be unable to diplo-annex them because of your incredibly high BB (high BB means they will not be Very Unlikely, or worse, to accept DA).
If attempting to quietly Diplo-annex (DA) a peaceful world:
- Have zero or one ally, so that you get plenty of alliance offers. (Alliances are hard to ask for - but readily offered by some nations, if you have no allies. Two allies seems to be where you will get almost no offers.) Only choose allies you can turn into a vassal: Same Religious group and they have a monarchy (for a Royal marriage). Reject offers by Theocracies or Republics.
- When your ruler has low diplomatic skill:
- Build relations with these allies, mostly using gifts.
- If relations are better than ~30, ask for Military Access (instant +10 relations).
- When over ~150, ask for Royal Marriage (another instant jump), although they usually already offer an RM by this point (and save you a diplomat).
- When 190+, ask for Vassalization. They will usually jump at the chance.
- Then, rudely cancel the Alliance (-50 relations), so that you are free for offers from others, and not drawn into unintended wars.
- Put your diplomats to work again, to keep the relation high.
- Focus on the vassals who are most important in the near term (see below); the long term will take care of itself.
- Build relations with these allies, mostly using gifts.
Yes, it's long and slow work, and plenty of Gifts that result in 0 relation increase. But it's a way to keep all those undiplomatic rulers or councils building an all-important platform for your precious few very diplomatic rulers. Once you get a ruler with high diplomacy (range is 3-8; 6 or esp. 8 is high):
- Focus on DA targets ones with the highest diplomatic skill (mainly). But strategic value and longer vassalization (30 years max) can guide your choice, too.
- Then DA the rest, in decreasing importance / likelihood.
- Regardless of strategic importance, do not intensely court new-found allies up to vassals when you have a high DIP ruler (unless he has little else to do diplomatically). There will be a 10-year wait, and maybe a lot of relation building, before they are eligible for DA. A lot can happen in the meantime; both your ruler and theirs can die. Let boorish rulers handle it. If you have a diplomatic ruler, cash in your chips on good vassals you've built up already. A bird in hand is worth four in the bush.
- Don't forget that, while large vassalized nations might be enticing, it will be a long time before you can successfully DA anyone again (due to Badboy). That said, though, you have still DA'd as much as possible in the most efficient way possible, if you are coming from a "badboy over time" approach. And your high DIP ruler can easily set up other nations as much as possible for future DAs.
This is a "slow but sure, then fast and quick" way to DA countries. If you like to DA, it's also a way to feel comfortable during the times your monarch has a low value in the all-important diplomatic skill: When your ruler shouldn't be allowed outside on a leash, you're building your empire for the time when you do have a ruler who lights up every room she or he enters.