Japan is going ahead with plans to develop its own stealth fighter jets to compete against the rapidly advancing Chinese air force and other threats to its air defenses, officials said. The Defense Ministry aims to develop a prototype stealth fighter that will combine advances in maneuverability, radar and stealth technology. The key part of the six-year project, to be officially launched next April, involves developing an XF5-1 engine that would allow a fighter jet to be both highly maneuverable and cruise at supersonic speeds. "We need fighters that are fitted with highly advanced technology, considering what's been developed in other countries," the ministry said in a recent statement. "It is a crucial project in developing fighters that will play a key role in our future fleet and build our space defense."