Doubling in blackjack is a strategy employed by player when they deem the total of their hand leaves them in a favourable position to beat the dealer. How to double In order to double down, you must place a bet equal to your original wager in exchange for one more, and only one more, card to be dealt to your hand. You can usually find blackjack games with rules that offer a house edge of less than 1%, and can often find games with a house edge under a half percent. If you don’t use basic strategy you can be playing with a house edge of 1.5% to 3% instead of a half percent. This quickly adds up. The dealer's strategy is extremely simple and unsophisticated - which is why blackjack is a beatable game. The house's huge advantage is position. It would be especially bad for the house if people recalibrated their play based on the fact that the dealer was now standing on 16 or hitting 17.

• Blackjack 21 Optimal Strategy Definition
• Blackjack 21 Optimal Strategy Example

Spanish 21 is a variation of the standard game Blackjack with a few differences. This article concentrates on those differences and assumes you know the basic rules of Blackjack. This can be found in this separate article if you need a refresher.

Spanish 21 vs Blackjack

The main difference between Spanish 21 and most other forms of Blackjack is that it is played with a Spanish deck of cards that has 48 cards instead of the usual 52 – the deck is the same with all 10’s removed.

As a 10 is an important card in all forms of Blackjack, you would have thought that this gives a huge advantage to the House. You would be correct if that was the only change, however, a number of other features have been added in an attempt to offset this. Spanish 21 actually has a slightly better edge for the player than many forms of Blackjack.

Spanish 21 Rules

• Late Surrender is allowed, not just after your first 2 cards have been dealt

• You are able to Double after a Split

• You can re Split Aces

• A hand with 21 always wins even if the Dealer also gets 21

• Blackjack always wins even if the Dealer also gets Blackjack

• You can Double at any time after as many cards as you wish

• You can normally Hit and Double after Splitting Aces – this can vary so is worth checking

• You can Surrender after Doubling, known as Double Down rescue. You lose your initial stake which is effectively getting back half your total outlay for the initial stake and the Double

Variation of Rules

Spanish 21 does have some variables which differ depending on where you play so be sure you check these before you start playing.

• Either 6 decks or 8 decks of cards are used

• The dealer can sometimes Hit or Stand on soft 17 – a hand that includes an Ace meaning the Dealer has 7 or 17

• Some casinos will allow you to Double a hand up to 3 times

• Some casinos will not pay the bonus amounts after you Split a hand

Above is an example of the layout for a Spanish 21 table. This particular version sees the Dealer stand on all 17’s, other than this you will see it is very similar to a standard Blackjack table.

Spanish 21 Odds & Payouts

Payouts and odds can be slightly different from regular Blackjack.

• A 5-card 21 pays 3 to 2, a 6-card 21 pays 2 to 1 and 7-card or higher 21 pays 3 to 1. This bonus doesn’t count if you have previously Doubled

• A hand consisting of 6-7-8 or 7-7-7 of mixed suits pays 3 to 2, if suited it pays 2 to 1. Either of these hands with all Spades pays 3 to 1. Again, this doesn’t count if you have previously Doubled

• A suited 7-7-7 when the Dealer has a 7 face up pay $1,000 if your bet is between $5 and $24 and a whopping $5,000 Super Bonus if your bet was $25 or more. If you are playing live with other players, they will each receive a $50 ‘Envy Bonus’ if this comes in.

Spanish 21 Strategy

There are several variable rules for Spanish 21, which affect some of the decisions for an optimal strategy. The below Spanish 21 basic strategy is based on casinos that use 6 decks and the Dealer stands on a soft 17, which is the most common variation of the game.

Hard Hands – No Ace

H = Hit D = Double D2 = Double except Hit with x or more cards
SR = Surrender S = Stand S2 = Stand except Hit with x or more cards

Due to the bonus if you get 21 with 4 or more cards, in some instances it is best to Hit and go for these, in the above chart the number next to an action denotes the minimum number of cards you need in order to Hit as opposed to Stand or Double

Soft Hands – With an Ace

H = Hit D = Double D2 = Double except Hit with x or more cards
S = Stand S2 = Stand except Hit with x or more cards

Due to the bonus if you get 21 with 4 or more cards, in some instances it is best to Hit and go for these, in the above chart the number next to an action denotes the minimum number of cards you need in order to Hit as opposed to Stand or Double.

Pairs

H = Hit D = Double
S = Stand SP = Split SP* = Split except for Suited 7’s in which case Hit

Double Down Surrender when you have 12-16 Vs 8-A, 17 Vs A

Never Split 4’s, 5’s or 10’s

Spanish 21 Tips

There are many extra things to remember in Spanish 21 compared to standard Blackjack, remember the extra bonus payouts for getting 21 with 4 or more cards and getting 7-7-7 or 7-8-9. These don’t count if you were to Double though, so in situations where you feel you have a chance to hit these, ensure you follow the table above for the optimal chance of winning.

Don’t be afraid to Surrender – It is better to admit defeat and get some of your bet back in certain circumstances than continuing and losing it all when the odds are against you. Spanish 21 gives you the chance to Surrender at any time, ensure you make the most of it to stay ahead of the game.

Play for fun first if you want to learn the game properly – This is especially important when playing Spanish 21 as there are different features and rules than in standard Blackjack. We, therefore, recommend you play with free chips until you get the hang of this version when you have a better chance of finishing up.

Always play only with money you can afford to lose – this is the same for all casino games which should be fun – if you don’t enjoy it or are gambling with money you cannot afford to lose your mindset will not help the situation giving you a bigger chance of losing.

Blackjack References:

How to Count Cards
Blackjack For Real Money

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Home > HARVEY_MUDD > HMC_FACULTY > HMC_FAC_PUB > 197

Student Co-author

HMC Undergraduate

Document Type

Article

Department

Mathematics (HMC)

Blackjack 21 Optimal Strategy Definition

Publication Date

1993

Abstract

In the casino game blackjack or '21,' mathematically determined best plays have been calculated by various mathematicians and gambling experts. These optimal playing strategies all assume that the casino pays even money on bets (excluding when the player has a 'blackjack'). However, many casinos offer the player 'lucky bucks' that pay the player either 3-to-2 or 2-to-1. In the usual game, the player's expected loss is under 1¢ per dollar bet. in this paper, we derive optimal strategies under luck-buck conditions, giving the player an expected gain of 26¢ or 55¢ per dollar bet.

Rights Information

© 1993 Consortium for Mathematics and Its Applications (COMAP, Inc.)

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Recommended Citation

Benjamin, A.T., & Huggins, E. (1993). Optimal blackjack strategy with 'lucky bucks'. Journal of Undergraduate Mathematics and Its Applications, 14(4): 309-318.

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