In a technical advance off San Diego, a U.S. Navy F-35B strike fighter landed on a Japanese aircraft carrier for the first time over the weekend, proving that the two allies can jointly use one of the world’s most sophisticated jets. The short takeoff vertical landing (STOVL) aircraft touched down on the JS Kaga on Saturday afternoon, the Navy said. The carrier arrived in local waters earlier this month for six weeks of developmental testing and exercises with the Navy and Marines. The 814-foot Kaga is a destroyer that was converted into an aircraft carrier to help Japan better defend itself and to collaborate with the U.S., possibly in helping keep sea lanes open in the South China Sea. China has said that it has the right to control marine traffic in that region, a claim rejected by President Joe Biden. “This test does not merely enhance the capabilities of the (Japan) Maritime Self-Defense Force,” Shusaki Takeuchi, the Kaga’s commanding officer, said in a statement. “It also improves the interoperability between Japan and the U.S., strengthening the deterrence and response capabilities of the Japan-US alliance, thereby contributing to peace and stability in the Indo-Pacific region.” The Kaga had to paint its flight deck with heat-resistant material so that it can withstand the F-35B’s thrust engines, the Navy said. Some defense analysts consider the F-35B is the stealthiest military aircraft in the world. This version of the plane is primarily used by the Marine Corps, which is part of the Department of the Navy. The San Diego-based aircraft carrier USS Abraham Lincoln is currently carrying its own version of the plane — the F-35C — during operations in the Middle East.