Why the world should be wary about Japan's nuclear arms remarks?

Recently, a senior Japanese official floated the idea of Japan acquiring nuclear weapons.

While Tokyo quickly called it a "personal view", this wasn't just an offhand comment. It was meant as a trial balloon, testing Japan's commitment to one of its most fundamental postwar pledges: the Three Non-Nuclear Principles.

For Japan, adherence to its no-weapons pledge shouldn't just be about external pressure, it is a duty conferred on it by history and conscience.

Video editor: Gao Yidi (intern)