The name of the game is to beat the Bank, in the person of the Dealer, without exceeding 21. These bonuses don’t exist any more, but the principle remains the same.
If your first two cards were the jack of spades and an ace, you got an extra payout. It became popular in American gambling circles where bonuses were invented to keep players playing. Helena, Blackjack became popular across the pond after the French Revolution. Based on ‘21’, a popular card game from the 18th century, much loved in particular by Madame du Barry and later by Napoleon, who played it to pass the time while in exile on St.