personal view: the thing with japan is that after ww2 they got heavily disarmed ,they focused only on defensive military . Now ,after the Ukraine war and the problems they face with China(and north Korea) they decide to increase the military budget ,just like everybody else “if my neighbor is buying a gun ,shouldn’t I also have one ?” Everybody says that we are at the start of the second cold war ,I tend to belive it .
But if your neighbour is only buying guns because your “friend” (who hates your nbr) keeps putting his into your place - why should you get your own too? That will only lead to further escalation. Contrary, you should try to actually throw your friends guns out and reason with your neighbour.