- Two round-robin groups of five players each.
- All matches best-of-three.
- Top three players from each group advance to Challenge: Second Stage.
- Bottom two players are eliminated from SSL and must re-qualify.
- Prize money:
- Each series awards ₩300,000 (≈$265)
- ₩200,000 (≈$175) for the winner, ₩100,000 (≈$90) for the loser.