I got it, too. Sorry, but playing the Shimazu can be a mutha!
First I got going, made some newb mistakes but still got rolling, when I was attacked by a former friendly who got nervous.
And hit me when my forces were depleted by terrible battles.
With an army at least as big as all my forces.
OK, so I did some decent damage. I still was going to get stomped, because while my troops were reinforcing it was just taking too long, and they had knee-capped by second army.
So I restarted.
This time I made them my ally and cooperated via marriage, making them a much more reliable friend. While I’m unsure of how far I can allow them to exapnd, I think I’ll be able to move fast enough. I almost feel like I’m playing Europa Universalis, with its complex diplomatic balancing acts.
My current enemy’s campaign AI isn’t giving me any help, however - they’re tricky and keep their armies mobile and large. Sometimes they will send a force too small, and that’s when you pounce and then strike back. But they’ve been surprisingly strong, and unfortunately I simply haven’t had time to stand back and build my forces. So far I’m about 20 turns in and have a large army trying to cripple the north end of the island’s defences. If this works (and I have their whole army beseiged, I’ll be able to roll up their other settlements quickly. Down the line my lord’s son will probably turn on his current allies, but that’s for another day. Further, they hunted down and killed off three of my four trading ships, though I’m building a fleet to make sure that doesn’t happen again. Still have money, though. Markets are very useful, even if you don’t build them up further. Roads are no longer the best thing you can build, and there’s some real choice about what you want to build.
I will probably go Christian, for the guns. I’m just not happy with the way masses of archers tend to work out. In fact, I’ve been (ahistorically) positioning archers behind the melee and then rushing them into the thick of it to break the enemy lines once all forces are engaged. The AI tends not to handle this well - it can unit-match, but it doesn’t know what to do if you flank that effectively.
I also like that happiness management is easier. In previous games, I often would crank up my taxes and then fill the cities with huge hordes of old units and peasants, partly because a heavily-damaged unit was useless and if retrained lost all its bonuses. Now I want to keep my good units, and if they have to rest for a while it’s no problem. - they’ll be back in action in a year or so. Once I own all of Shikoko I will probably turn my baleful gaze on the Chokosabe, and then begin rolling up the southern end of Japan (or on the in-game map, the western end of the main island of Honshu)