How to get Personal Unions?

[SeraphLance]

In my 214 hours of EU4, I have never been involved in a personal union, whether on the subject side of things or otherwise. No Iberian Wedding, no PLC, nothing at all. Well, okay, except silly things like starting as sweden.

I know the gist of how it happens... Royal Marriage with someone, they die without an heir, you use the claim throne option. What I'm less sure about is how it "actually" happens. Either something else is required, or nobody ever, ever dies without an heir. Am I missing something?

[Kagemin]

Claiming the throne only really makes a difference if you want to enforce a union through war. If you plan on doing that you can claim throne as soon as someone of your dynasty has no heir or a heir with only a weak claim, which happens fairly often (right after a new king rose to power, when a heir dies, etc).

Other than that this guide has the mechanics summed up pretty well from what I saw:
http://steamcommunity.com/sharedfiles/filedetails/?id=293290169

From my experience the Succession Wars with rival nations are usually the most common way to gain PUs, apart from wars.

[Liquid]

I had my first Personal Union (kinky) as Ming with Oirat. Seriously, their ruler just kicked the bucket and *bam* P.U. baby!

[Funsize]

This guide on the Paradox forum is also strongly recommended. The text formatting is kind of bad, but the information is pure gold.

http://forum.paradoxplaza.com/forum/showthread.php?788829-guide-to-royal-marriages-personal-unions-and-claim-throne

A. No dynasty, no heir - Claim throne (if King over 40) - AIM is to put your dynasty on throne to open up future possibilities.
B. No dynasty, weak heir / regency - Do nothing
C. Same dynasty, no heir - If you can win a war, Claim throne and use Casus belli to force PU. If you can't win a war, check you are the highest prestige same Dynasty RM, if so claim throne and hope they don't get an heir before dying for PU, if neither, work on improving your prestige!
D. Same dynasty, weak heir / regency - If you can win a war, claim throne, use Casus belli to force PU.
E. succession war as defender/attacker - If defender, you're going to war. If attacker, only attack if you can win war against PU'd country, defender and it's allies, otherwise don't press.
F. You inherit the throne - hooray