I won the second game I played as Nanbu. They start in a nice position to quickly absorb smaller nearby clans. I basically absorbed the whole northern area while playing nice with the two larger clans which remained to my south (One of the three got eaten by the other two). When these two decided to fight it out, I declared war on one of them and devoured most of the clan.
I had about 5-7% of Japan about this time and Uesugi was tied for 1st with 13-16%. I was invited to a plot to attack Uesegi by my southern neighbor, although I was pretty skeptical about our prospects for success should the plot trigger. The plot did trigger, incidentally, with nearly all of Uesugi's neighbors suddenly at war with them. I got lucky in that the Uesugi decided it would direct 99% of its armies to my southern neighbors while I took kori after kori away from the Uesugi. I decided to white peace with them for a while so both sides would weaken eachother further while I focused on other things, but rejoined soon after when I was invited to a plot to attack the Uesugi again. After I had absorbed the Uesugi the game was essentially won for me, the rest just involved mopping up. I was a bit surprised by the lack of plots against me the entire game. I suspect that my leader's insanely high intrigue stat had something to do with it, but I'm unsure. I had some real lucky breaks in this game, and I am sure that there can be much variation between each game.
Some funny things that I noticed in my game were the following:
1. Yamana was completely absent by the time I was looking at that section of Japan. I have no idea when they disappeared or even what happened to them. In place of a super Yamana/Ouchi there was a fairly large Kitabatake clan which had basically devoured both. Other large notables were Toki and Takeda
2. Ashikaga clan broke free from Uesugi during the massive war and managed to secure half a dozen kori that were quite spread out.
3. Takeda spontaneous split into two around the time I finished with Uesugi. They were fairly decent in size pre-split and made their conquest much easier.
4. Kitabatake clan, which was 2nd largest at like 11-15%, decided it would become subjugated by my clan without a single combat occuring. (I guess this is something that will be addressed in future patches)
All in all it was an enjoyable game. I still have a lot to learn though, especially regarding the best use of ninjas and the sow discontent mission.