North Korea rocket revives Japan pre-emptive strike talk

"Since the incident proceeded without direct impact on Japan, I think we are not going to get the hard focus we got in 1998."

That year's launch of a North Korean long-range missile over Japan prompted Tokyo to speed up deliberations and eventually sign up to the ballistic missile defense system it is now building in cooperation with the United States.

While many believe direct strikes on North Korea would be difficult to justify, beefing up the missile shield on which Japan has spent more than 66 billion yen ($654.9 million) over the past five years is a more acceptable option for some commentators.

"We cannot of course destroy their missiles in the territorial air space of North Korea," said foreign policy expert Yukio Okamoto, who favors more focus on a system to intercept at the rocket booster phase.

"We ought to have a more strategic defense system and a lot of research and development is needed for that," he said. "I think we should aim at that and I think there is a strong thrust toward that direction now."

Ruling Liberal Democratic Party (LDP) lawmaker and former defense minister Yoshimasa Hayashi agreed.

"There are two cases for pre-emptive strikes," he said. "One is before they launch, the other is the boost phase. Legally speaking, the boost phase could be easier than attacking the base even before they do anything."

The main difficulty in that case would be technical, with a laser strike from a satellite the most feasible option, he said.

($1=100.77 Yen)