If a country claims that it sticks by the three non-nuclear principles but at same time hoards far more nuclear materials than it needs, including a massive amount of weapon-grade plutonium, the world has good reason to ask why. Outlined by Prime Minister Eisaku Sato in a speech to the House of Representatives in 1967, the three non-nuclear principles, an important part of Japan's peaceful post-war development, state that Japan will not produce, possess or allow the entry into its territory of nuclear weapons. However, since Prime Minister Shinzo Abe took office a year ago, clamoring for developing nuclear weapons have often been heard from Japan's right-wing conservatives. As a signatory to the Non-Proliferation Treaty, Japan should adhere to its international obligations. As the world's only victim of nuclear attacks in the final stage of WWII, it should clearly understand the horrible consequences of nuclear proliferation. However, five decades are not long enough for the island country, where some politicians wish, openly or privately, for nuclear arms, to return the 331 kilogram of weapon-grade plutonium -- enough for 40 to 50 nuclear bombs -- it received from the United States during the Cold War. Some Japanese experts have said that, with necessary amounts of weapon-grade nuclear materials, their country is capable of developing nuclear bombs within a year. Adding to the world's concern, Japan is also reportedly hoarding more than 1.2 tons of enriched uranium and another 44 tons of plutonium, which overwhelmingly dwarf its civilian demands. The ecological and environmental catastrophe of the Fukushima Daiichi nuclear disaster in 2011 had clearly showed that the superabundant nuclear materials are actually time bombs for a seismically active country like Japan. What's more, storing more than necessary nuclear materials is also against the regulations of the nuclear watchdog, the International Atomic Energy Agency, which require countries to keep a balance between the demand and supply of nuclear materials. The somewhat obsessive possession of nuclear materials is not the behavior of a responsible and reliable country, as Japan portrays itself in the international community. It brings nothing but doubt and suspicion to the already volatile East Asia. If the Japanese government truly wants to play a constructive role for regional stability, it should honestly explain its reluctance to the world and return the stored nuclear materials as soon as possible. After all, Abe and his cabinet have already caused too much trouble to regional peace and stability.