Basically what is the earliest time that the Imperial Court can regain control of Japan from the Shogunate? Was it only possible when the Meiji Restoration occurred? Could the Kenmu restoration, the last time the Emperor held any power before the Meiji Restoration, be successful? What about during the Sengoku or Azuchi–Momoyama periods? Or could the Imperial Court somehow manage to remain in control of Japan, keeping any Shogunate from being formed in the first place?