Blinds
Forced bets posted by the two players left of the button before any cards are dealt.
The small blind and big blind exist to guarantee there's something to fight for. In a $1/$2 game the small blind posts $1, the big blind posts $2, the button moves one seat every hand, and the blinds move with it. Without them the optimal strategy would be to fold everything but aces, and poker would have died in the saloon.
Blinds are a cost you pay on a schedule, and it's worth knowing the price. At a nine-handed $1/$2 table you pay $3 per orbit — about $10 an hour at live pace. Any profit you show for the night is made after that toll, plus the rake. This is why "folding everything" isn't neutral: it's a slow bleed. The game is fundamentally about winning more than your share of pots to cover the forced payments.
They're also a positional puzzle. The big blind gets the best price in poker to defend: facing a raise to $6, you call $4 more into a pot that will be $13, so you only need about 31% equity — which is why good players defend wide and bad players donate. Posting when you return to the table, straddles layered on top, and antes added later are all rule questions your home game should settle in writing before they come up mid-hand.
Stakes are named after the blinds for a reason — they set the scale of everything: buy-ins, pot sizes, and what an hour of play costs. When you track sessions, the blinds define the unit your win rate is measured in, so record them every time. That's why serious players count results in big blinds rather than dollars — it keeps the score honest whenever the stakes change.