Updated August 10th, 2023

Playstile 2LO Tournaments

Playstile 2LO (aka Playstile Two Loss Out) is a new tournament structure for official KeyForge tournaments that combines the best features of Swiss-style pairings and double-elimination. The goal of Playstile 2LO tournaments is to provide a structure where all matches contribute to a player’s chance to win the tournament and reduce round-to-round byes (and associated wait times) to a minimum. In addition to achieving these goals, Playstile 2LO is also very efficient and will usually result in the tournament reaching a top cut one round sooner than other tournament structures.

This tournament structure will be used in all sanctioned KeyForge events starting August 18, 2023.

Summary

Playstile 2LO tournaments consist of two stages: qualifying rounds, and finals. Qualifying rounds are conducted by pairing players within the tournament until they either lose twice, or qualify for the finals (aka “make the top cut”). After two losses, a player is eliminated from the tournament.

There is no bracket like traditional double elimination. Instead, after round one, players are placed within a “pool” of either “Undefeated” or “One-Loss” players and paired within these pools each round (see Pairings, below).

Play continues until the tournament reaches a stage known as the “top cut” which is the stopping point where a certain number of players are qualified to pass to the final stage of the tournament. In KeyForge tournaments, the top cut currently consists of eight players who will advance to the final round (the final round uses single-elimination over two rounds, and then a best-of-three series in the final match).

Playstile 2LO’s top cut is formed when the number of Undefeated players is equal to or less than half the size of the top cut. These players immediately qualify for the top cut, leaving half or more of the remaining slots to be filled by One-Loss players.

Depending on how many One-Loss players remain, pairings will continue in qualifying rounds until an additional round would eliminate too many players to fill the remaining top cut slots. Tiebreakers among remaining players, if needed, is first resolved by Strength of Schedule (S.O.S.) comparison, and then (if needed) a tiebreaker round.

Tournament rounds

A Playstile 2LO tournament is played over a series of qualifying rounds which continue until every top cut slot has been filled by a qualifying player. The top cut will consist of a combination of undefeated players and one-loss players, with the number of each depending on the total number of players in the tournament. The exact number of qualifying rounds needed to reach a top cut also depends on the total number of players in the tournament.

For example, in a tournament with 128 players, four players will be undefeated after five qualifying rounds (they will each have a 5-0 win/loss record). Those four players will immediately qualify for the top cut. Two additional qualifying rounds will be needed to determine which of the remaining players will qualify for the other four top-cut slots (a more detailed example is found later in this page).

After the top cut is determined, the tournament will proceed into the finals. In KeyForge tournaments, the top cut is comprised of 8 players who will play two single-game elimination rounds, and a final match of best-of-three.

QUALIFYING ROUND PAIRINGS

First round pairings are completely randomized among the entire participant base. After the first round, half of the tournament’s participants will have their first win, creating the initial Undefeated pool of players. The other half of players will have one loss, creating the initial One-Loss pool of players.

Subsequent rounds will randomly pair players within their respective pools. This means that Undefeated players will only play other Undefeated players. The same is true for the One-Loss pool of players. When an undefeated player is defeated for the first time, that player moves into the One-Loss pool for the next round.

Pairings during the qualifying rounds are additionally constrained to opponents that have not previously played each other in the tournament, unless there is no other pairing option available.

Byes

If there are an uneven number of participants in a given round, it will be necessary to assign a “bye” to a player for that round. The bye will be assigned to a randomly determined player who receives a win for that round. A player that has already received a bye cannot receive another bye in the tournament, unless all remaining players have already received one bye each.

UNDEFEATED TOP CUT

After a certain number of qualifying rounds (the exact number depends on the total number of players at the start of the tournament), there will be a number of undefeated players equal to half the number of top cut slots or less. Usually, this will consist of four undefeated players. Rarely, it could be as few as three or two undefeated players. As soon as this situation occurs at the end of a round, the undefeated players immediately qualify for the top cut and no longer play in qualifying rounds.

Run-Off Rounds

Once the top cut has qualified the undefeated players, if the size of the One-Loss pool is double or more than the slots remaining in the cut, then the One-Loss players will continue to be paired in run-off rounds. Pairings in run-off rounds work the same as qualifying rounds.

When the number of One-Loss players is less than double the number of top cut slots remaining, run-off rounds are finished. Then, a tiebreaker will determine who qualifies if there are still more players than top cut slots available. Strength of Schedule determines tiebreaker. In the rare event when two or more remaining players are tied for the bottom tier of Strength of Schedule, these ties will be resolved in one or two additional tiebreaker rounds.

Strength of Schedule

Strength of Schedule (S.O.S.) is a rating of how difficult a player’s opponents were over the course of the tournament (for more information, see the Strength of Schedule Calculation below). This calculation of opponent strength is used as a tiebreaker when there are less slots available in the top cut than players remaining. A higher S.O.S. means that a player is ranked higher in the standings than a player with lower S.O.S.

Tiebreaker Round

There is a rare possibility that players may be tied for the 8th or higher positions in final standings because their S.O.S. is exactly the same. A tiebreaker round between those players must be played to determine their exact placement and thus who will qualify for the top cut.

Finals

Once the top cut has been determined, the tournament proceeds to the finals stage. The finals consist of two single-elimination rounds and a final match. In the initial round single-elimination rounds, undefeated players are paired against one-loss players when possible. In KeyForge, the final match is played as a best-of-three series.

Tournament Example

Below is an example of Playstile 2LO in action. This tournament has 128 registered players to start. After five rounds, four players are undefeated; those four players advance to the top cut. After seven rounds, five players have only one-loss each; the four with the highest strength of schedule advance to the top cut, and the fifth player with the lowest strength-of-schedule is eliminated.

Ghost Galaxy will run these tournaments using the Playstile service (which is currently in beta with plans to open to the public later this year). The Playstile software handles the pairings, table-number allocations, byes, unforeseen player drops, and tracks S.O.S. (Strength of Schedule). We are confident that this system will provide both fast, fair, and enjoyable tournaments.

For those players interested in the heavy nuts and bolts of the Playstile 2LO format, you may consult the “Advanced Concepts” below.

Playstile 2LO – Advanced Concepts

The concepts described above are meant to be an overview for anyone interested in this new and innovative format and what to expect when attending an Playstile 2LO event. Additional explanation of more advanced concepts and scenarios can be found below.

Assigning Pair-Ups and Byes

During the tournament there may be an uneven number of participants within the Undefeated pool of players. This will not assign a bye to an Undefeated player. A “pair-up” will happen where a random player from the One-Loss pool will be selected to play a random Undefeated player. This will follow the constraint of not rematching players who have already played.

Tournaments where the total number of participants is uneven will require one assigned bye per round. This will be assigned randomly in the first round, while in subsequent rounds the bye will be given to a random player in the One-Loss pool.

An Undefeated player would not receive a bye after the first round unless all the remaining One-Loss players had received a bye. Additionally, a player would receive a maximum of one bye unless all other players had also received a bye. Either scenario is extremely unlikely.

Strength of Schedule Calculation

Playstile 2LO uses a Strength of Schedule (S.O.S.) calculation made after all pre-cut game rounds have been completed. It takes into account the “Win Rate” of a player’s opponents, and also the Win Rate of the opponents of a player’s opponents. These metrics are called “OWR” and “oOWR” respectively, and they are added together for a player’s total S.O.S.

OWR is calculated by taking the total number of wins across all of a player’s opponents (match wins + byes) and dividing it by the total number of games played by those opponents (wins + byes + losses). This quotient is then multiplied by two for the purposes of weighting this number.

Calculating oOWR requires finding opponents of a player’s opponents. The wins of all these players are summed (wins + byes) and divided by all games played by those players (wins + byes + losses).

A player’s S.O.S. for a given round is the OWR + oOWR.

It’s important to keep in mind that S.O.S. calculations should only be used to compare two players with the same win record.

Example S.O.S. Calculations

After seven rounds, Scott and Josh each have a record of 6-1.

Scott’s opponent’s across those seven rounds had a total of 20 wins, 12 losses, and 0 byes. Scott’s opponent’s opponents had a total of 92 wins, 56 losses, and 0 byes. Scott’s S.O.S is calculated like this:

Scott’s opponents: 20 + 0 (wins + byes) / 32 (games played) * 2 = 1.250

Scott’s opponent’s opponents: 92 + 0 (wins + byes) / 148 (games played) = 0.622

Scotts S.O.S. at the end of round 7 is thus 1.872 (1.25 + 0.622).

Josh’s opponent’s across those seven rounds had a total of 19 wins, 14 losses, and 0 byes. Josh’s opponent’s opponents had a total of 113 wins, 53 losses, and 0 byes. Josh’s S.O.S is calculated like this:

Josh’s Opponents: 19 + 0 (wins + byes) / 33 (games played) *2 = 1.152

Josh’s opponent’s opponents: 113 + 0 (wins + byes) / 166 (games played) = 0.681

Josh’s S.O.S at the end of round 7 is thus 1.833 (1.152 + 0.681).

Player Drops and Disqualifications

Players may wish to remove themselves from the tournament. This is called a “drop.” The player is eliminated from the pairing pool and will no longer play in additional rounds.

A player may drop between rounds or after being paired for their next match. If a drop is recorded between rounds, the dropped player is simply not included in the pairing pool. If a drop is recorded after pairings, the dropped player receives a loss and their opponent receives a win. This is not counted as a bye for the player’s opponent.

Similarly, if a player is disqualified from a tournament by the marshal for a serious rules infraction or breach of conduct, the player is eliminated from the pairing pool and will no longer play in additional rounds. If a player is disqualified after pairings, their opponent receives a win for the round, which is not counted as a bye.