In Korea, high school baseball (고등학교 야구) is played at a very high level by students who train year round. Unlike in Japan or the U.S. where nearly every high school fields a team, there are only about 60-70 Korean high school baseball teams which makes the competition tantamount to an all-star league of Korea's young talent. KBO, MLB and NPB scouts are frequently in attendance at all of the five national high school baseball tournaments.
The five Big 5 tournaments are the most important high school baseball events of the year in terms of tradition, prize-money awarded, and public attention.
There used to be four lower-level high school baseball events of the year sponsored by local cities. However, these local tournaments have been replaced with the High School Weekend League after the 2010 season.