I'm playing a RotS campaign on hard with battle realism. On the battlefield, I'm raw, can pull heroic victories outta my *** using the tactics I've employed over several of these titles.
I'm having some major diplomatic woes. I'm playing as the Taira family (Fukuhara? the dark red one), and for once I'm not employing ruthless imperialistic expansion strats. I'm actually a nice trade partner, back up my allies, don't declare war on anyone. I've taken a few small provinces via my junetawhatever diplomat fella, and I've slaughtered the pesky Minamoto armies that can't resist encroaching on me from the west. So, after spending 30 turns or so beefing up my core central cities (Settsu, Kyoto, Omi), I have 4/6 of the naval trade destinations maxed out with 10 trade ships each, minimal naval defense (too much upkeep cost!) I decided to go on a Western offensive push. I got tired of accepting their pathetic peace treaty offers just to have them go back on their word.
Long story short (sorry, rambling here), as soon as I started making progress and took a few enemy provinces, the ENTIRE remaining country of Japan declared war on me in a SINGLE TURN. I think literally about 12 nations did all on one turn. The other big clans (Minamoto and Fukiwaja or w/e - blue and green clans) have even ALLIED together, which I assumed would not happen.
I've got every little nation in Japan blocking isolated strips of my naval supply lines, impossible to keep up with, I've got armies coming in from every angle. I smash them all, but with a NEGATIVE income for almost 10 turns now, it looks like my goose is cooked.
What the hell should I have done differently? I avoided full blown war with everyone for so long only to have them all team up and decide it is time to send me to oblivion.