ABOUT EU LCS
The League of Legends Championship Series (LCS) is the preeminent League of Legends esports league in North America and Europe. Each LCS league (NA and EU) is comprised of 10 teams facing every other team twice over the course of the season, for a total of 18 games each. Matches are played in a Best of 1 format, with each team playing once per day. The competition stretches across two splits, Spring and Summer.
At the end of each split, the top seven teams will automatically re-qualify for the LCS. The 8th and 9th place LCS teams will then play in a Promotion Tournament against the 2nd and 3rd place Challenger Series (CS) teams to retain their spot in the LCS. The 8th place LCS team will get their choice of CS opponent. The 10th place LCS team will automatically be relegated to the Challenger Series, while the 1st place Challenger team will automatically qualify for the LCS.
For more informations: The complete LCS Rules document can be downloaded here.