Enlarge By AP A prototype of the Chinese J-20 stealth plane is seen during a runway test in Chengdu, southwest China. BEIJING — Defense Secretary Robert Gates will complete his China visit with a trip Wednesday to the nation's most famous defense system, the 5,500-mile long Great Wall. But it's the latest, less conspicuous addition to China's armory that grabbed headlines Tuesday. As Chinese websites splashed pictures and video of the first test-flight of the J-20 stealth fighter jet Tuesday, China's President Hu Jintao gave the first official confirmation of the test in a meeting with Gates, who said he asked Hu if the flight had been timed for his trip. Hu "said that the test had absolutely nothing to do with my visit and had been a pre-planned test. And that's where we left it," Gates told reporters, according to the Reuters news agency. The U.S. currently operates the world's only fully operational stealth fighter, the F-22 Raptor. Russia is also developing a stealth fighter, so-called because of its capacity to evade radar detection. Some military analysts said Tuesday that the J-20's 15-minute test-flight, over an airfield in the southwestern city of Chengdu, was timed both for Gates' China visit, which ended a year of stalled military links between the two nations, and just ahead of President Hu's state visit to the USA next week. The flight sends a "determined message" that "China is prepared to compete with the USA," said Arthur Ding, a cross-strait military affairs expert at the National Chengchi University in Taipei. "Even as the USA and China are finding ways to put relations back on track, that won't stop China deploying and developing more advanced weapon systems," said Philip Yang, a political science professor at National Taiwan University and founder the Taiwan Security Research website. On his flight to China Saturday, just weeks after the first pictures of the J-20 appeared on websites, Gates told reporters that "what we've seen is that they maybe are somewhat further ahead in the development of that aircraft than our intelligence had earlier predicted." U.S. Vice Admiral David Dorsett, director of naval intelligence, admitted China's emerging military capabilities surprised the U.S. "They've entered operational capability quicker than we frequently project," he said in an interview posted January 6 on the Pentagon's website. "We've been on the mark on an awful lot of our assessments, but there have been a handful of things we've underestimated." While he repeated U.S. concerns about a lack of transparency by China's military, Dorsett highlighted a change of tactic by the People's Liberation Army. "Over the years, the Chinese military doctrine was 'hide and bide' — hide your resources and bide your time," Dorsett said. "They now appear to have shifted into an era where they're willing to show their resources and capabilities." The new fighter's progress will be watched most closely in Taiwan, the self-governed island that Beijing regards as a renegade province. China broke off military links with the USA last January in response to the Obama administration's proposed $6.4 billion arms package to the island. "Taiwan still enjoys certain theater advantages, but a fighter like that, if developed, could be used in anti-intervention in this region, so it could complicate the overall strategy and military preparedness," said Philip Yang. China fast-tracked the J-20 following the U.S. deployment of F-22 fighters in Guam in the last three years, their temporary deployment in the U.S. base in Okinawa, Japan, last year, and use during military exercises with South Korea, said Yang. Arthur Ding cautioned that "it's easy to assemble a jet fighter, but we need to see what kind of mission or function this jet fighter can execute," and how much the J-20 relies on indigenous versus imported technology. It could take ten years for China to achieve real progress, he said. "At this stage it's only a psychological impact, it shows China's determination to spend tremendous resources to develop new fighters," said Ding. We've updated the Conversation Guidelines. Changes include a brief review of the moderation process and an explanation on how to use the "Report Abuse" button. Read more