Though it had larger diameter than the H-IIA launcher, the H-IIB launcher was derived from the H-IIA. JAXA and MHI Launch Services sought to take the learning from developing the H-IIA and apply it to a launcher which could handle the needs of cargo re-supply to the International Space Station. After the HTV was retired, the H-IIB launcher was as well, given that it no longer had a purpose.
The H-IIB saw nine lauches between 2009 and 2020, all successful. The payload in all cases was the HTV on a mission for providing cargo re-supply to the International Space Station. These missions were operated by JAXA.
Derived from learning coming from the development and operation of the H-IIA, the H-IIB was designed specifically to support launch of the HTV spacecraft for re-supply of the International Space Station.
