Japan on Friday signed a formal agreement with the United States to buy an initial four F-35 fighters built by Lockheed Martin Corp and other equipment for 60 billion yen ($756.53 million), a company spokesman said. The letter of offer and acceptance, which was signed in Japan, includes four conventional takeoff variants of the F-35 fighter at a cost of 10.2 billion yen ($128.61 million) each, a slightly higher price than the 9.9 billion yen ($124.83 million) than Japan initially budgeted to spend. But the cost of the two simulators and other equipment dropped to 19.1 billion yen ($240.83 million) from the anticipated level of 20.5 billion yen ($258.48 million) so the overall price remained at 60 billion yen. The signing was good news for Lockheed and the F-35 program, which is looking to orders from Japan and other countries to help maintain economical production rates at Lockheed's main F-35 plant in Fort Worth, Texas, despite cuts in U.S. orders. Japan (…) announced in December that it plans to buy a total of 42 F-35 fighters.