Japan has completed its first successful commercial launch of a foreign-made satellite.
The H-2A rocket blasted off from the space centre on Tanegashima Island in southern Japan at 1:39 am on Friday (16:39 GMT Thursday).
The South Korean satellite separated from the rocket 16 minutes after launch, followed by three Japanese satellites.
This marks Japan's entry into the launch business.
The South Korean satellite, the KOMPSAT-3, is a multipurpose observation satellite developed by the Korea Aerospace Research Institute, said a Japan Aerospace Exploration Agency (Jaxa) press release.
One of the Japanese satellites, the Shinzuku, would be used for monitoring global ocean currents and the other two smaller satellites were experimental models, officials said.
This was the 21st launch of the H-2A rocket developed by Jaxa, which is reportedly working on a next generation H-3 rocket.
Mitsubishi Heavy Industries (MHI), which has operated the rocket since 2007, is looking to carry out more commercial launches, joining the race in a space dominated by the Europeans and Russians.
Japan has been on a decades-long quest to be part of the commercial launch business.