The NBA regular season is long enough that a bad month barely registers. The playoffs are the opposite: everything is decided in a series against one opponent, over and over, until two teams are left.
Who gets in
Each conference, Eastern and Western, sends eight teams to the playoffs. The top six in each conference qualify automatically, seeded one through six by regular-season record.
The seventh through tenth-placed teams enter the play-in tournament. The seventh and eighth-placed teams play each other, and the winner takes the seventh seed. The ninth and tenth-placed teams play, and the loser is eliminated. The loser of the 7-8 game then plays the winner of the 9-10 game for the eighth seed. Two games to get in if you finish ninth or tenth; one comfortable route if you finish seventh.
The bracket
Once the eight seeds are set in each conference, the bracket is fixed: one plays eight, two plays seven, three plays six, four plays five. The NBA does not reseed between rounds, so a lower seed that pulls off an upset keeps the path it earned.
Every series is best-of-seven, in a 2-2-1-1-1 pattern. The higher seed hosts games one, two, five and seven; the lower seed hosts three, four and six. Home advantage means four possible home games out of seven, and it goes to the team with the better regular-season record.
Four rounds
First round, conference semi-finals, conference finals, then the NBA Finals between the two conference champions. Sixteen wins required in total. The Finals use the same 2-2-1-1-1 structure, with home advantage going to whichever finalist had the better overall regular-season record, regardless of conference.
Why series basketball is different
A seven-game series lets coaches solve each other. Rotations shorten, a bench player who was useful in January disappears, and a defensive scheme that worked in game one gets picked apart by game four. Teams that rely on one offensive pattern tend to be exposed; teams with two or three ways to score tend to survive.
It also removes luck. A single game can be decided by one hot shooting night. A series rarely is, which is why the NBA champion is usually the best team rather than the hottest one.
Play-in: the argument
Critics said the play-in punished the seventh and eighth seeds for a season already completed. In practice it did something more useful. It removed the incentive for a team drifting out of ninth place to stop trying in March, because ninth is now a live playoff position rather than a dead end.
The short version
Six automatic qualifiers per conference, two more through the play-in, a fixed bracket, four rounds of best-of-seven, sixteen wins to a title.