Japan moved closer to securing the right to develop Iran’s largest oil field, shrugging off U.S. efforts to stop allies from making major energy deals with the nation. Japan signed a letter of intent with Iran on Sunday in which it agreed to spend USD 10 million to help fund a seismic study of the Azadegan oil field, which contains an estimated 26 billion barrels of oil. The two countries also signed an energy co-operation agreement.