What Units do you Consider Essential for Japan?

I don't know about anyone else but when making up builds for Japan, I use the Formations quite a bit. They do save some points & you get a decent force to field.
Just my experience here but it does work for me.
I also will include "Captured French Vehicles" on occasion. Panhard Armored Cars, R-35 tanks & P107 halftracks see use often. I also got a couple trucks from the Secret Santa a couple years ago & the Russian trucks proxy as well. Mobile Japanese are great!