The development of an air blown two-stage entrained flow coal gasification system for power generation had been newly succeeded with the achievement of one month stable and continuous operation of the 200 t/d pilot coal gasifier. The MHI's IGCC system (HERCULES) composed of the air blown two-stage entrained flow coal gasifier, the fixed bed dry gas clean-up system and a 1 300 degrees centigrade class gas turbine, enables the highest net power plant efficiency in the world. HERCULES greatly improves the economy and secures the reliability, which will be realized in the 2 000 t/d IGCC demonstration plant in Japan.