China's new stealth jet just entered service - and it exposes a huge weakness for the US
On the surface, China's quick turnaround on the J-20 and other defense projects outpaces the US, where the F-35 Joint Strike Fighter, first flown in 2006, still struggles to meet operational requirements in its naval variant.
The J-20, which bears some resemblance to the US F-22, also raises questions about the extent to which China has been able to steal US military secrets.
Furthermore, China built the J-20 specifically to counter a weak point in the US Air Force - unarmed aerial refuelers and airborne early warning and control aircraft.
A senior scientist working on stealth programs told Business Insider the J-20's stealth isn't all aspect or nearly as effective as its US counterparts. However, the J-20's stealth on the front end and extremely long-range missiles make it ideal for knocking back US support planes and keeping the US Air Force away from the battle.
Peter Singer, a strategist at New America and author of Ghost Fleet, a novel which depicts a World War III situation between China, Russia, and the US, told Business Insider that this fits in with a larger strategy from the Chinese called "assassin's mace."
According to Singer, in the middle ages, "Chinese assassins would carry a little mace under their sleeves" when facing a guard armed with a long sword.
Instead of the assassin carrying their own long, conspicuous sword to match the guard's strength, the assassin used a mace specifically designed to smash the guard's sword, turning his strength into a weakness.
China's J-20 brings this ancient strategy into the modern world.
"These things you see as your strengths, we're going to invert that," said Singer, describing Chinese military doctrine.