In American blackjack, or blackjack with Vegas rules, the dealer receives both cards right away, one face-up and one face-down. If the face-up card is an Ace, the dealer will peek at the other card to check if he has Blackjack. If he does, the hand ends. The dealer only receives one card in European blackjack before the players get their two cards, which means the dealer can't check for Blackjack.