With N. Korea provoking them for decades, I'm surprised they have kept article 9 of their constitution.
It made sense to defang Japan in the post-war period, but unilateral disarmament is foolhardy --and they know it given they have SDF as a workaround the limitations... so given they are by no means foolish, why keep on being somewhat hamstrung by article 9, specially given N. K's behavior?