The new anticipated timetable for the J-20 hardly augurs the end of American military dominance. But it wasn’t the only Chinese military development that took the Pentagon by surprise last year.

According to the Pentagon’s new report (.pdf) on the Chinese military, China’s got three nuclear-powered submarines — an advance that Helvey conceded the U.S. military didn’t anticipate. China also fielded an “improved” amphibious assault vessel last year, while the U.S. Marine Corps is having trouble upgrading its own.

And that’s just the stuff that the Pentagon can see. Helvey speculated that the Chinese military keeps its research, foreign military acquisitions and nuclear modernization off its books. The report estimates that China’s declared $106 billion annual military budget is really more like $120 to $180 billion.

None of that means China’s military will overtake America’s anytime soon.