Key Resolve, previously known as Reception, Staging, Onward Movement, Integration (RSOI) which was previously known as Team Spirit even earlier, is an annual command post exercise (CPX) held by United States Forces Korea with the Republic of Korea Armed Forces.
It is conducted between February and April and focuses on United States Pacific Command OPLANs that support the defense of South Korea.
Additionally, US units are moved to Korea from other areas and they conduct maneuvers and gunnery exercises.
ROK units also conduct maneuvers with some acting as the Opposing force (OPFOR).
[3] Japan supports the joint drills of South Korea and the US, considering it to be a deterrent power in the Asian-Pacific region.