Wikipedia - K4 League

The K4 League is the fourth-highest division in the South Korean football league system. It is regarded as the successor to the K3 League Basic, the second division of amateur K3 League founded in 2017.

Since 2021, Korea Football Association has allowed reserve teams of the K League to join the K4 League.

Sydkorea - K-League 4 er den fjerde og laveste division i det sydkoreanske fodboldsystem. Ligaen består af 10 hold, som hver spiller 27 kampe i løbet af sæsonen. De to bedste hold rykker op i K-League 3, mens de to dårligst placerede hold rykker ned i K-League 5.