The aim of blackjack it to get as close as possible to 21 without actually going over 21.
The dealer, (the bank), is also trying to the the same, in the end, whoever is the closest wins.
A picture card is worth 10 points and an ace has a value of 1 or 11 other cards are worth their values.
The dealer has some basic rules he must follow, anything below or equal to 16 and he must draw a card, and anything above 16 and he must stand, (not get any other cards).
So much for the basics
Casinos have introduces variants of the game to make more exiting but more often than not it is to increase the house edge, in other words it will increase the odds of the casino winning.
Spanish 21 allows a lot more flexibility, doubling down any number of cards, rescue, (or surrender).
Other variants offer extra bonuses, payout for five or more card that add up to 21’s.
A 21 that is achieved with the cards, 6-7-8, (in that order or not).
Or 21 with 7-7-7, (with various bonus if they are the same suite of 7’s for multiple decks).
Late surrender of the cards.
Sometime the casino will always pay the player 21 even if the bank also gets 21, (they make more money that way as they don’t pay the normal 3/2 in the case of blackjack.
Pontoon is an english variation with many strategy and rule changes.
The French and German variant “Vingt-et-un” (Twenty-one), “Siebzehn und Vier” (Seventeen and Four) don’t include splitting.
Chinese Blackjack is played by many in Asia.
Double Exposure Blackjack is a variant in which the dealer’s cards are both face-up, this game normally increases house edge by paying even money on blackjacks and players losing ties.
Double Attack Blackjack has very liberal blackjack rules and the option of increasing one’s wager after seeing the dealer’s up card. As with Double Exposure Blackjack the odds are firmly in the dealers favour.
Recently, thanks to the popularity of poker, Elimination Blackjack has begun to gain a following. Elimination Blackjack is a tournament format of blackjack.
It’s a Spanish thing.
With correct basic strategy, a Spanish 21 almost always has a higher house edge than a comparable BlackJack game.
Certain rules changes are employed to create new variant games. These changes, while attracting the novice player, actually increase the house edge in these games.