Short answers, pulled from the story.
A bye allows a team or player to advance automatically without playing a match. This mechanism ensures tournament brackets remain balanced when the number of participants does not match powers of two.
The American Football League gave each of its nine teams two bye weeks during the 1966 season following the addition of the Miami Dolphins. The league returned to using a single bye week in 1970 to extend the sixteen-game schedule across seventeen weeks.
Each of the seventeen teams in the National Rugby League receives three byes every season after the admission of the Dolphins in 2023. At least one club must have a bye in every round to maintain scheduling balance.
FIDE allocates pairing-allocated byes to the lowest-rated eligible player to ensure fairness regardless of initial ranking status. No player may receive more than one bye throughout an entire event unless specific conditions apply.
Studies from 2002 to 2010 indicated that teams returning from a bye week held a significant 2.2-point advantage over teams without this break. Data from 2012 to 2023 shows this advantage reduced to just 0.3 points due to stricter rules limiting practice time.