If you will be splitting, you have to do basically the same as above, but landing the main heir is no longer optional.

Optionally before handing out kingdoms you can also increase the amount of given counties by +1, land your main heir and transfer all the other vassals under them when you feel its time. Easiest way to get it is to probably educate your heir and hope to trigger the event where he'll get the trait. If you wish to view a searchable list of ALL commands, see Commands.gg/ck2. If you are within a single main title, all you need to do is, at any moment in time, give each extra heir the same amount of counties you (plan to) have plus an extra one if you have more heirs than second-to-highest titles (for example you have 4 heirs, but your empire only has 2 de jure kingdoms), ideally in their own de jure duchy/kingdom, and all de jure titles up to the second highest (you have to create those). It's not guaranteed, but at least the chances are reasonable.Don’t postpone until all females involved are infertile or you get all the land you plan to get in this life or whatnot, start the process as soon as you have an extra heir.Don’t take a younger one as an extra/replacement. From terrain to advantage you shant lose another battle. If you are having multiple spouses/concubines, make sure their age is roughly the same. In one game of Crusader Kings 2, my pudgy, brown-haired character and his pudgy, brown-haired.

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