Can't figure out what I'm doing wrong

[KissBlade]

Graeme puts out a lot of good tips you should probably follow. Also with Jomon, try to prioritize taking mountain and forest provinces around your capital first. Remember castles take resources from neighboring provinces and mountains and forest produces the most resources. Also I literally build almost nothing but samurai archers with jomon. They are pretty much the superior unit compared to the rest of samurai line.