A new medium size/medium range supersonic stealth fighter bomber concept (JH-X? H-X? J-X?) has been studied at the 601 Institute since 2000s. It appears to feature a twin seat cockpit and twin engines. A mock-up (head section?) was constructed at SAC during 2013. The design was rumored to have subsequently been rejected but resurrected later at 603/XAC to be further developed into a medium stealth bomber. The current status of this project is unknown.