Is there any easy way to determine if you're going to start a world war in Divine Wind? The UI doesn't really seem clear on what will and will not cause a cascading alliance. I've gotten hopelessly rusty after playing so much CKII. I also miss "war goals" with a passion usually reserved for women.
You want to vassalise that mangy one province minor with that mission you got? Think again, SPONTANEOUS QUADRUPLE SUPERPOWER ALLIANCE!
Ahhh, those were fun times. I remember getting all of europe into a war by trying to vassalize Meissen, with me(Burgundy) and most of the HRE and France (even though I wasn't emperor, just VASSALIZED EVERYTHING) Against Spain, Scotland (who ate England after I beat England in a war), Portugal, Poland, Norway, Sweden, Granada (who was catholic for some silly reason), Lithuania, a few Italian minors, and Sicily. 'Twas fun, though I couln't vassalize most of them because they were either too big or infamy was too high. So I waited out a decade or two for provinces to defect.
What I learned is that the AI for having tons of allies in a fight sucks. I had about 200k allied troops from all my vassals sitting outside a province with.... 20k enemy soldiers. Why? Because every individual country in that stack had less, and nobody thought to work together. So I had to bring some of my 300k standing army around to attract the horde into an ongoing fight, which they would all gladly do.