What caused the unity of japanese shogun to fall apart?

The main driver of the downfall of the shogunate was the exposure to outside countries, specifically their weapons systems. The shogunate had made very limited use of firearms. However, outsiders, such as Admiral Perry, made clear just how far the Japanese were behind in terms of their military capabilities. This drove the overthrow of the shogunate and the beginning of the Meiji period of modernization.

3is faulse becaues the big so that wpuld mean thtmat they are farther apart.

Word of mouth.