Still figuring out how to play the Date on hard difficulty. I might just have to try it on Normal. I first played the Chosokabe on normal and that was just too easy. I would run over everyone no problemo. Figured I would try the Date which is a step up and then on Hard. Not sure if its just the Date or the difficulty setting but its a crappy area to start. You pretty much have to take the Mogami first but my issue was right after the Hatakeyama start knocking on my door. Then all 5 of their allies war with me as well and it becomes a clusterfuck. This all within 15-20turns.
Might try allying yourself with some of those clans in the first few turns.