Black Desert Korea's publisher DAUM just announced that the upcoming closed beta of Black Desert will last for about three weeks while the first CBT lasted for only one week.
The amount of testers will be five to six times more than that in the first closed beta, and there were about 5,000 testers in last CBT. Players can apply for beta keys through official methods as well as the previous Facebook event. To my knowledge, it requires the Korean identity to register a DAUM account. That could be one of the problems for a western Black Desert fan to play this game on Korean server in addition to the IP-block setting.