North Korea's latest nuclear test has reignited a sensitive debate in Japan about strengthening its military, which is barred from offensive action under the country's post-war pacifist constitution.
Pyongyang's communist regime on Monday staged an underground nuclear test thought to be up to five times more powerful than its maiden 2006 test and also launched several short-range missiles, sparking international condemnation.
In the wake of the latest threats, Japan's conservative ruling party has suggested that Japan's Self Defense Forces should be allowed to launch a pre-emptive strike on a country if a missile attack is imminent.
The party's defence panel has proposed the plan be included in new national defence programme guidelines to be announced later this year.
"We won't sit and wait for death," said Gen Nakatani, former defence chief and now head of the Liberal Democratic Party's security panel. "We have to have an active missile defence on top of a passive one."
For now, Japan is under the "umbrella" of the joint US-Japanese ballistic missile defence (BMD) programme, and relies on information from the US, its main ally, to alert it to a missile threat.
Mamoru Sato, an analyst at Tokyo think-tank the Okazaki Institute, said debate on changing Japan's defence posture is long overdue.