Chi upgrades until i hit the farming techniques. I then switch to Bushido until i can master whatever arms my clan is famous for. Mostly until "way of the x", then i look at my strategic position and see what would benefit me more.

If clans are switching to Christianity i'll push down the Zen path for Monasteries and + to monk actions, otherwise I will stick to Bushido and try to get more of an advantage on the battlefield.