TOKYO — When Yasunari Kawabata became the first Japanese to receive the Nobel Prize for Literature in 1968, he gave a speech called “Japan, the Beautiful, and Myself” that presented a benignly aesthetic portrait of the so-called Japanese spirit larded with references to classical poetry, the tea ceremony and ikebana. When Kenzaburo Oe received the prize in 1994, he titled his lecture, “Japan, the Ambiguous, and Myself,” and offered a critical take on the country’s ambiguities, starting its being part of Asia and simultaneously aligned with the West.

I was reminded of the contrast between Japan the Beautiful and Japan the Ambiguous late last month when, during the third Nuclear Security Summit in the Hague, the Japanese government announced that it would hand over to the United States more than 700 pounds of weapons-grade plutonium and a vast supply of highly enriched uranium. It struck me then that the ambiguities of Japan’s policy on nuclear weapons might be coming up against the nationalist agenda of Prime Minister Shinzo Abe, also the author of “Towards a Beautiful Country: My Vision for Japan.”

Although Japan does not have nuclear weapons, it has a nuclear weapons policy. The strategy was set out by the Ministry of Foreign Affairs in 1969 in an internal document whose existence was kept secret until the daily Mainichi Shimbun published it in 1994. That paper states that “for the time being we will maintain the policy of not possessing nuclear weapons” but also “keep the economic and technical potential for the production of nuclear weapons, while seeing to it that Japan will not be interfered with in this regard.” Known as “technological deterrence,” this posture is inherently ambiguous, and has been made more so still by the ministry’s insistence that the document was a research paper rather than a statement of policy.

In a 2000 essay about the future of the Nuclear Nonproliferation Treaty, the disarmament advocate Jonathan Schell drew a distinction between capacity and intention in describing the range of positions states may adopt on nuclear weapons. At the time, Sweden had the capacity to produce such weapons but not the intention; Libya had the intention but not the capacity. Japan, by contrast, stands out as the only nation that has both the capacity and the intention to produce nuclear weapons but does not act on its intention. It has pioneered a type of nuclear deterrence that relies not on any overt threat, but on the mere suggestion of a latent possibility.