In blackjack, a box refers to the area on the table around which the dealer and player cards are dealt. The dealer starts the hand by dealing two cards face down to each player, then sets the remaining cards in the box face down.
The player can peek at their two cards, but must keep them concealed until they make their first bet. .
Once a player has made a bet, they can either peek at their two cards or show them to the dealer. If a player shows their two cards to the dealer and they are both identical, then the dealer can either give them another card or keep them.
If a player shows their two cards to the dealer and one of them is different, then the dealer gives them another card and turns over another card from the box. This new card becomes part of the player’s hand and replaces one of their original two cards.
If a player has no more cards in their hand after revealing all of theirs and/or any replacement card given by the dealer, then they lose that hand.
