Avoiding Realm Divide?

[Jungle Rhino]

My tips for RD are:

1. Save up a slush fund ~100,000 koku ought to do
2. Save up a couple of princesses for marriages to key clans - marry them off a couple of turns beforehand for maximum diplo++
3. Make sure your Daimyo is has high honour - this can get you +30 relations with some clans
4. Do not overlook the + diplo techs, and retainers. It all adds up.
5. Focus on a tax based economy with as many high level farms as possible running a big food surplus. Trade is for mid-game expansion and cannot be relied upon. Never let your army upkeep exceed your tax income during the mid game or you will founder post RD.
6. Form vassals after RD both to trade, and as a means to quickly pacify an unruly, or religiously different province.
7. Bomb the cr@p out of any enemies of a different religion with monks - one game I reduced Ito from having all of the southern island to two provinces with a prolonged monk/ninja campaign of rebellion/sabotage/assassination. You can do all this without actually declaring war :) Also, unlike vassals rebel provinces never backstab you and don't expand. By filling portions of the map with rebelling provinces you can pave the way for swift conquest without filling up your RD bar.
8. Economise your defenses - construct large castles at key choke points - the free garrisons there save you an enormous amount of upkeep.
9. Build a navy to cover your a$$ - Honma or somebody like them will declare war on you and dump a stack in your backfield.
10. Get a night attack general for an easy capture of Kyoto - or breaking up large enemy stacks.