Explain the rise of militarism in japan in the early 1930s

Japan was already on its way to becoming militant since the late 19th century when the Meiji Restoration brought with it a philosophy of being a strong nation with a strong military. Its victories in WW1 (it was an Ally) against Russia and its need for resources (Japan is a resource-poor country such as in terms of oil and rubber) also drove it as it continued to industrialize. Seeing how the West had explored imperialism, Japan also embarked on a number of actions to do the same in the 1920s. 
By the time the 1930s came around, Japan's military culture was incredibly powerful and influential. Unlike other military forces, like those in the United States, its civilian oversight was weak allowing its own military office to dictate orders on its own which it often did. This led to Japan's interference in China and, eventually, its takeover of Manchuria in the 30s. It would also set the stage for the start of their land war in China in 1937 in an attempt to take over the country and plunder its resources for the good of Japan.

I hope that this is the answer that you were looking for and it has helped you.