The play-in tournament occupies the few days between the end of the regular season and the start of the playoffs, and it exists to answer one question: should finishing seventh be treated the same as finishing tenth?
The three games
Four teams per conference take part: the seventh, eighth, ninth and tenth-placed finishers.
Game one: seventh hosts eighth. The winner is the seventh seed and is done. The loser is not eliminated.
Game two: ninth hosts tenth. The winner survives. The loser is eliminated, season over.
Game three: the loser of game one hosts the winner of game two. The winner takes the eighth seed. The loser is eliminated.
So the seventh and eighth-placed teams get two chances to claim a playoff spot. The ninth and tenth-placed teams must win two elimination games, the decisive one away from home.
Why the seeding matters so much
The asymmetry is deliberate. A team that finished seventh over eighty-two games should not be knocked out by one bad night, so it gets a second life. A team that finished tenth has to earn its place the hard way. Home court in every play-in game goes to the higher-placed team, which is another small reward for regular-season position.
What it changed
Before the play-in, a team sitting eleventh in March had a clear incentive to lose: a better lottery position was worth more than a meaningless finish. The play-in pushes that cliff edge down the table and makes tenth place genuinely valuable. More teams stay competitive later into the season, which is exactly what the league wanted.
It also produces a specific kind of pressure. Play-in games have playoff intensity with none of the safety of a series. A team can be excellent for six months and be gone in forty-eight hours.
The criticisms worth taking seriously
The strongest objection is that it can punish a good team. A seventh seed with a solid record still has to win a game it would not otherwise have played, against an opponent with nothing to lose, and can end up in the lottery.
The counter-argument is that the gap between seventh and tenth over a full season is often three or four wins, which is noise rather than a hierarchy. Making those teams settle it on the floor is arguably fairer than a table that treats a four-game gap as decisive.
The short version
Seeds seven to ten, three games, two playoff places. Seventh and eighth get two chances. Ninth and tenth must win twice. Then the real playoffs start.