Yes realm divide has just happened, not that it will make any difference as any clan you come into contact with when one of your provinces hits their borders, turns hostile towards you if not immediately, after a few turns. Had to fight Takeda and Hojo simultaneously, them both being allies. Also had Tsutsui walking through their provinces into mine, as they were also allied with them. Wiped out Hojo a while ago/ Takeda has been causing quite a few problems, especially when they walked past me into the middle of my base with 1 and a half stacks of troops, and Imagawa clan popped its head up and decided to attack me from the front with a full stack, so I had to choose who to deal with first. Now have most of it under control, an army on the north of the map, and an army on the south, pushing into the middle with both armies and centralising them, before moving west and sending each army north/south again, with the hope of finishing off takeda.
I'll post a couple screens of my current map situation.