We were discussing the origin of the widespread claim that Japan is “six months” from a bomb—and the earliest scholarly reference I could find was Richard Halloran’s Chrysanthemum and Sword Revisited: Is Japanese Militarism Resurgent. Halloran argues:

Japan also has the financial and technical resources to make nuclear weapons. A Japanese strategic thinker said years ago, and recently reaffirmed it, that “Japan is N minus six months.” He meant that Japan could build a nuclear weapon within six months of a political decision to do so.112

112. Conversations with the author in 1976, 1990 and 1991.

It is worth noting that the claim is made in passing; Halloran is making the point that Japan has the capability but not the desire to go nuclear. Whether it is six months or three years, doesn’t really matter to him.

It seems, though, that the “six month” idea dates to the mid-seventies—at a time when John Endicott’s careful study, Japan’s Nuclear Options, suggested a much longer timeframe.

I’ve been reluctant to speculate about why Sankei received this particular leak. Sankei is an extremely conservative paper, which I remember carrying some headline grabbing stories about extensive cooperation between DPRK and Iranian nuclear programs (I’ve posted two such stories in the comments).

Anyway, a reader familiar with Japanese media and its relationship with the Japanese government offers these thoughts:

With regards to the recent Sankei Shimbun article (and comments on the potential for Japan going nuclear) there’s one aspect to this story that should be mentioned.

The report, supposedly “leaked” to Sankei and citing the 3 – 5 year timeline for going nuclear, was most likely passed on to that newspaper by government officials deliberately.

Sankei is Japan’s most conservative publication, with strong ties to the ruling Liberal Democratic Party and the defense establishment. Although Sankei is the smallest national daily, the other papers are quite used to Sankei “scooping” them on these types of stories, since it’s an open secret that they have a direct line to the top levels of the government.

When the original Sankei article first came out, many of my colleagues and I interpreted this as a clever way for the Japanese government to send a subtle message to China. While publicly rejecting nukes, this is one way to say to China “the clock’s ticking” meaning that Beijing has to get serious about disarming North Korea, and fast.

China monitors virtually all Japanese news media, and even obscure articles are routinely translated into Chinese and often find their way into Chinese papers and websites. The Sankei article didn’t make a huge splash in the U.S., but it definitely raised eyebrows in China.

And PM Abe’s policy on this point is in contradiction. While publicly assuring China that Japan won’t go nuclear, he’s commissioning studies into the idea and encouraging public debate.

I am by no means an expert on proliferation, but I know how strongly Japanese citizens loathe North Korea. And the government has been taking a much stronger line than in the past (something the public has been urging for decades).

Should the six party talks fail and North Korea increases its arsenal, with China twiddling its thumbs, then I think it is highly likely that Japan will develop its own detterent, even if in secret a la Israel (although it’s unclear yet how they would work around the NPT).

But if they do it out in the open, then it won’t be too difficult to convince their public while NK is holding 10 or more weapons with delivery capability. China’s arguments against will be extremely weak, given NK’s history of terrorism and threats.