With the killing of the second Japanese hostage by Islamic State there seems genuine anger in Japan as demonstrated by Prime Minister, Abe. Japan is not known for its emotions but there were real tears in the Prime Minister's eyes; and the mother of the second hostage was beside herself with grief on hearing the news of the death of her son.
The second Japanese hostage knew the risks he was facing yet perhaps not even he thought he would be captured and executed by Islamic State.
Japan has highly powerful armed forces but since world war 2 they have not fired a shot in anger and because of its world war 2 constitution drawn up by the victorious US occupation forces Japan cannot take unilateral armed action, only in self defence may it act.
Japan has a proud history of a martial past as outlined by the tradition of Bushido, the Samurai, Ninja and of course Karate. Its history is very similar to the feudal system and chivalry that operated in Europe. However Japan has to tread carefully, as does Germany, because of its atrocious war record during world war 2; but, that does not mean that the land of the rising sun cannot be a military power again on the world stage.
Japan is not only facing a common enemy with the west with Islamic extremism but also lives in a dangerous neighbourhood of the world, where you have old rival China and, of course, North Korea. Although, as mentioned earlier, Japan has a large army, navy and airforce, Japan since the end of world war 2 has depended largely upon the United States for its defence, and US forces are still based to this day in Japan.
Certainly this awful execution of both Japanese hostages will give those in Japan ammunition for Japan making a more assertive military presence on the world stage. Prime Minister, Abe, himself has stated from the word go he would like to see a more beefed up Japanese military able to stand up for itself and come out of the shadow of the United States.
Of course, Japan is a free country not occupied by the US any more but both countries are tied together and Japan would probably have to negotiate with America should the Japanese self defence only constitution be altered allowing Japan to take military action in response to groups like Islamic State.
I, for one, would not fear a resurgent Japan. In fact, it would give the west a strong ally in our fight with: Islamic extremism; in the permanent stand-off with North Korea, and help to contain a growing Chinese super power.