I’m not to fond of rely in tech rolls for a strategy myself. I might do tech rolls as Japan if Germany is about to fall.
What’s the point of spending all your money, losing territory and income so that by the time your empire is just about doomed you get some techs. Pity you don’t have any money to leverage the tech.
However if Japan is in a strong income position and gets Ind Tech or Hvy bmbrs they might survive if Germany falls. Any other tech is kinda useless towards late stages of the game IMHO.
BB