A natural or BlackJack is when on the first two cards a player receives  a 21 combination, in which case he wins automatically if no one else has a BlackJack as well, if the “upcard” of the dealer (a hole card is a card facing down and upcard is a card facing up) is a 10 or an Ace, the player will have the ability to take insurance if house rules allows, by placing a side bet, against the probability that the dealer has a BlackJack, if he wins he wins the hand and the hand of all the players on the table without a BlackJack.