Under agreement with NASA from 22 December 2015 JAXA will collaborate under ISS program until 2024. It should not surprise that tradition of one launch for every year of Kounotori cargo spacecraft is still continued in 2016. Kounotori is unmanned cargo spacecraft launched on atop H-IIB rocket. Without navigation system necessary for autonomous docking, Kounotori is put into desired orbit and next is approaching to about 10 m to ISS. After reaching desired position it is grabbed by Canadarm2 and docked to free port of Harmony module. JAXA is utilizing Kounotori to resupply Japanese Experiment Module since 2009 - spacecraft is able to take up to 6000 kg during one mission; 4500 kg in pressurized and 1500 kg in unpressurized conditions. Kounotori could not be used for returning cargo to Earth - after utilizing it is undocked burns in atmosphere.
H-IIB is larger version of H-IIA rocket utilized first time in 2009 for lifting Kounotori during its first mission. It is basing on two stages supported by four boosters. Stages are liquid fueled. Comparing to H-IIA, H-IIB is longer for 3.6 m, offers payload capacity for GTO missions at 8000 kg (H-IIA - 6000 kg) and during ISS missions 16500 kg.
UPDATE 10/08/2016:Launch of the HTV was postponed due the unspecified reason; JAXA will announce new date as soon as possible.