The Japanese armed forces are about to change their name and role as a reaction to increasing Chinese expenditure on its military. As a result of growing tensions in the region and the head on clash with China over the Senkaku Islands (or Diaoyu Islands, if you prefer Chinese) Japan feels threatened by China’s aggressive approach of conflicts and recent military power build up. The Japanese army is called “Self-Defence Forces (JSDF)” which directly makes clear the current role of the forces, namely defensive, which is a result of World War II peace agreements that state that Japan may not have an offensive army and which also has been incorporated in Japan’s constitution, written by the United States in 1949.
International politics and power balances have changed a lot since 1949 and chances that the United States will oppose a Japanese rearmament or change of role are very small. Nowadays Japan is an ally of the U.S. and significant threats in the East Asia region are no longer coming from Japan but from China, which is America’s new opponent. American and Japanese forces are conducting military exercises on regular basis and a stronger Japanese army (probably supported by the U.S.) indirectly benefits U.S. influence in the region.
Currently, the Japanese army is a unique military force, or to be more precise, a unique group of civilians with defensive tasks. The army consists of civilians and the translation of the Japanese word for the JSDF has the word “group” in it with no reference to a military meaning. Not being a military force, doesn’t mean the JSDF doesn’t have any offensive capabilities at the moment. It’s fleet has frigates, corvettes and destroyers, there are over 350 fighter jets and 900 battle tanks. It is more a matter of doctrine and regulation which limits Japanese possibilities to use offensive force when necessary.
It seems that just waiting for China to act and react to that doesn’t fit Japan any longer and they want to be able to act to threats effectively, without being restrained by the constitution. This is a very game changing development with big consequences for the region’s stability. China’s reaction to this statement won’t be very light I guess, so this could induce further escalation in the long run.