According to the Kyodo News, the East China Sea resource development committee under the ruling Liberal Democratic Party (LDP) has decided to demand the government file an arbitration case against China at the Permanent Court of Arbitration in accordance with the United Nations Convention on the Law of the Sea (UNCLOS), so as to prevent China from drilling for gas and oil in East China Sea.

If the report is true, Japan will be the first country to take substantive actions following the South China Sea arbitration. Should Japan launch arbitration over the exploitation of oil and gas in the East China Sea, following hot on the heels of the South China Sea arbitration, China will be known internationally as the recurrent target of arbitration. This will double pressure on China.

Japan has no grounds for arbitration regarding many of its maritime claims. For instance, only a few square meters of the maritime feature of Okinotorishima are above the water at high tide, but Tokyo claims a 200-nautical-mile exclusive economic zone (EEZ) around it.

The width of the East China Sea is 360 nautical miles, therefore, the 200  nautical-mile EEZs claimed by the two nations overlap. Japan proposed demarcation at the median line while China has proposed applying the principle of the natural prolongation of a continental shelf under UNCLOS. Since China's continental shelf is longer than Japan's, the two are locked into a stalemate.

The Chunxiao gas and oil field is positioned on the Chinese side of the median line. Its location is indisputable as it falls into China's EEZ no matter what. But Tokyo has asserted that China's drilling could inadvertently drain Japanese gas through a honeycomb of seabed rocks. Meanwhile Japan has attempted to explore oil in disputable areas and tried to force China to accept its proposed demarcation.

If Tokyo launches an arbitration case over gas and oil fields in the East China Sea, it faces a high chance of losing. China opposes it because it follows a consistent policy of avoiding resolving territorial and maritime demarcation disputes through arbitration.

Tokyo has previously agreed to solve the issue through negotiation. The two sides reached a common understanding with regard to the principles guiding the joint development of the East China Sea in 2008. But this process was disrupted after bilateral relationship worsened with the Diaoyu Islands crisis.

If Tokyo insists on arbitration, the driving force would be likely its domestic right-wingers' extreme emotions. It is willing to create more waves against China through arbitration despite the risk of losing.

China has accumulated more experience of dealing with maritime disputes from the South China Sea issue. Through island construction in the Nansha area, it has acquired permanent strategic assets. International arbitration has forced China to pay a diplomatic price, but in general the country has gained far more than it has lost.

Tokyo benefited nothing from its nationalization of the Diaoyu Islands, where China has established a regular patrolling mechanism in the region. If Tokyo initiates arbitration over gas and oil fields in the East China Sea, it must expect a new loss.