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Humidity is important for infection control ...! Easy way to "enhance barrier function" # 145

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The book "Discover Twenty-One", a heart-poor dietary habit, once a week has exceeded 1 copies in a month.

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black Jack

black Jack(English: Blackjack) IsPlaying cardsUseGameKind of.casinoIn a card game played inpoker,バ カ ラIt is a popular game alongside. The player aims to get a higher score than the dealer so that the total score of the cards does not exceed 21 points. BaccaratOicho CubIt is a game similar in style.

Pontoon,21 (twenty-one)There is also another name.

United KingdomToCrazy eightSystem of blackjack (black Jack), but the rules are completely different.


originally21The origin is unknown.Don QuixoteAuthor ofMiguel de CervantesIs also gambling, and his book "(Spanish version)] The main character in the workIkasamaI have a teacher combination set up a squid.In this work, it means 21 in Spanishtwenty oneYou can see the name.

There are various theories about the name blackjack. As a local rule in the United States, the black symbolク ラ ブOrspade Ofジ ャ ッ クAndAce of spadesThe theory that the part consisting of is called "Blackjack" and has a bonus. And a French historian(English edition)Is it wrongKlondike Gold RushIncluding the gold they called blackjack when the miners were playingSphaleriteAdvocated the theory that it was named after[1].

how to play

player TheDealer (body)We have a one-on-one match with. In other words, when there are multiple players, the dealer will play at the same time as the multiple players.

The goal of each player is21The total number of cards on hand should be close to 21, so that the score exceeds that of the dealer.

The number of cards in your hand is exactly the same for cards 2 to 10, and the number of face cards K (King), Q (Queen), and J (Jack) is counted as 10. A (ace) can be counted either 1 or 11, whichever is convenient.

When each player completes the first bet, the dealer deals two cards to all participants, including himself. One of the dealer's two cardsFace up (up card)You can see it and everyone can see it. The other card is face down. The face down cardHole cardCall. The dealer's second card is turned face up only after all the player's actions have been completed.

The player's card may be face up or face down depending on the casino, but it is customary to be dealt face-up in the rule of using 6 or more decks that are currently mainstream. At this point, if the player is 21 (only one combination of 1, J, Q, K, and the other is A) is possible)Natural 21OrNatural blackjackIf the dealer is not 21, you will get a payout of 2.5 times the bet.

If both the player and the dealer are Natural 21, it will be a draw. If the player is not Natural 21 and the dealer is Natural 21, the player will automatically lose.

In the next step, the playerhitorstandMake a selection. Some rules have additional rules besides hits and stands (see "Special rules" below).

Draw another card.
Action: Hit the table or beckon yourself.
Stand / Stay
Compete with the current score without drawing a card.
Action: Shake horizontally with palm down.

Players can hit as many times as they do not exceed 21. Over 21bustCalled (bust) and immediately loses the player[2].. When all players stand, the dealer opens his hole card.

The dealer must draw cards until his hand is 17 or above, after which he cannot draw additional cards. If the number of dealers exceeds 17, all standing players win. If the player and the dealer have the same score, it will be a draw. In the case of the combination of A and 21, it depends on the casino whether the dealer hits or stands.

At first glance, the game seems to be advantageous to players with many choices, but there is always the possibility of bust if you draw another card when the number of cards is 2 or more, which does not include A when two cards are dealt. Therefore, the player side is disadvantageous.

Special rules

Depending on the casino, there may be options other than hit and stand. Because any special rules will help the player[3], Instead of adopting these, if the player has reduced the dividend to 2.2 times if they win in blackjack, and some casinos adopt these rules only for units with a high minimum betting unit (minimum bet).

If the two cards dealt have the same number, you can play them in two by adding the same amount of chips as the first bet.In this case, one additional card is dealt to each of the divided cards, resulting in two hands. In some casinos, all cards that count as 2 (2, J, Q, K) can be considered as a pair.Also, in most casinos, A pair splits allow you to draw only one each after splitting.There is also a rule that you can split again if the same number is distributed after splitting.
Action: Place the same amount beside the first bet outside the betting box and spread two fingers into a V.
Double down
The player can double the bet after seeing the first two cards and draw another card. You can't add more and draw. Many casinos allow you to double down as many as the first number, but some casinos have rules that allow you to double down only when the total number of cards is 2 (or 2). There is also. Also, whether or not double down is possible after the split is different for each casino. In addition, in a casino where it is confirmed after the player's action whether the dealer is Natural 1, if the dealer is Natural 11,10, the player loses the bet increased by split or double down. There is a fine difference in the rule depending on the casino, regarding whether or not to return the original as a match.
Action: Place the same amount next to the first bet and point it with your index finger.
If the player is in a bad position and decides that he cannot win, he will give up half of his stake and get out of play.For example, if the dealer is A and there is a possibility of natural 21 and the player is 6 and the probability of bust is high.It is roughly divided into rules that can be surrendered before checking Natural 21 (early surrender) and rules that can only be done if it is not Natural 21 (late surrender).Many casinos do not employ surrenders, and the rules for adopting early surrenders are rare.
Insurance / Insurance
If the dealer's face-up card is A, you can get insurance by adding half the price of your first bet.If the dealer is Natural 21, the insurance premium will be refunded twice as much as the insurance premium, otherwise the insurance premium will be forfeited.For example, suppose a player is betting $ 2 first, the player's cards are 10 and 8, and the dealer's face-up card is A.If the player chooses insurance here, add $ 10 as an insurance premium.Conversely, if you do not select insurance, no additional premium will be incurred.After confirming the insurance intentions of all players, the dealer hides them from the players and looks up the numbers on the dealer's face-down cards.If the dealer's face-down card is 5, for example, it will be Natural 10.At this time, the face-down card is turned face up and the player's first premium of $ 21 is forfeited, but $ 10 is refunded as insurance premium and the insurance premium of $ 10 is also returned to the player.In this case, the player's profit and loss is ± 5.On the other hand, if the dealer's face-down card is, for example 0, and it is not Natural 3, the insurance premium of $ 21 will be forfeited and the dealer's face-down card will remain turned inside out as usual. Play (selection of hold or hit) is performed.This insurance is a stochastically unfavorable option for players, but many casinos offer this option.If the player is Natural 5, the same amount as the first bet will be paid at the same time the player declares insurance (even money).This is because even if the insurance is successful (21 times the tie for the stake, 0 times the premium and 2 times the total dividend), it fails (1 times the natural dividend for the stake, This is because the total dividend does not change even if the insurance premium is confiscated and the total dividend is 1.5 times the premium.If the dealer's face-up card is 1, J, Q, or K, the dealer may be Natural 10, but in this case insurance cannot be declared.

Super-simplified strategy

The following items are super-simple strategies for actually playing blackjack.By observing these matters, the casinoDeduction rateCan be reduced to 1% or less.However, this guideline is set on the assumption that you are always using a new deck immediately after being shuffled, and it is possible to further reduce the deduction rate by using a more advanced strategy.The dealer's hand is weak when the up card is 2 to 6, and strong when the up card is 7 to A.

  • Always split the A or 8 pair if you can. 4,5,10 pairs never split.The other pairs split if the dealer is weak, if possible, and not if the dealer is strong.
    • A pair should definitely split as it is likely to be 21 if split. If the pair of 8 is left as it is, it is the worst move of 16, but if you split it, it tends to be a fairly strong move, so it is advantageous to split this as well.
    • If you treat a pair of 5 as 10 as it is, it will be quite strong, and if you split it, it will be a bad move, so you should never split it. 10 pairs and 20 are almost the strongest moves, so you shouldn't split at the risk of getting worse. As for the pair of 4, 8 is fairly strong, but splitting tends to be a bad move, so it is better not to split.
    • There is no big difference in strength between the other pairs and the splits, so it is decided by the dealer whether or not they are likely to win.When the dealer is weak, it is better to split and double the stake to expand the chance, and when the dealer is strong, it is better not to split so as not to widen the wound.
  • Double down is a hard hand when the dealer is weak with 1-11 of the soft hand (hand that reads only one A as 16) and 18 of the hard hand (hand that does not have A or reads all A as 1). In 9 or 10, the dealer's up card is smaller than his total (however, some houses are forced to hit if the score is 11 or less).Do not do anything else.
    • Double downs from soft hands and hard hands of 9 or less are waiting for the dealer to burst.However, it does not burst at all, so you should not do it when your hand is not likely to become too strong (15 or less for soft hand, 8 or less for hard hand).Even if the stay is strong enough (19 or more), it is better to play with the same numbers without taking risks.
    • Double down from 10 and 11 of hard hand is a stronger handmade aim than the opponent.That's why I judge by comparing the dealer's up card with my total.Of course, if the dealer's up card is higher than your total, you should not double down, but even if there is a tie, the winning percentage in double down is fifty-fifty, but if you do not, you can hit again depending on your hand. It is better not to do it because the winning percentage will increase.
  • With a hard hand, when the dealer is weak, he stands when he reaches 12 or above, and when he is strong, he hits until he reaches 17 or above.
    • When the dealer is weak, there is a high possibility that it will burst, so it is best to avoid the risk of bursting yourself.When the dealer is strong, it is unlikely to burst, so I have to aim for at least 17 or more with burst preparedness.
  • With a soft hand, hit until the dealer is 18 or more when weak and 19 or more when strong.If it becomes a hard hand, follow the case of a hard hand.
    • Since there is no possibility of bursting from a soft hand, aim for a higher number than a hard hand because you can hit more bullishly.
  • Surrender only if you have a hard 16 that you cannot split and the dealer's upcard is 10.
    • A surrender who unconditionally admits a loss should basically not be allowed as he and the dealer can win any hand.
  • No insurance.
    • Insurance is actually a side bet that has nothing to do with the main game, but it should not be a probabilistically disadvantageous bet.

Basic strategy

Most casino games are designed to give casinos a statistical advantage over players in the long run.Among them, Blackjack has a wide range of choices on the part of the player, and by taking statistically optimal actions called "Basic Strategy", the advantage of the casino can be greatly reduced.Depending on the differences in the rules, the casino deduction rate is about 0.0% to 0.6% if the basic strategy is followed.Although rare, there are cases where rules are provided that give the player an advantage even when playing only with the "basic strategy".

The following strategy table determines the optimal action of the player based on the player's hand and the face-up card of the dealer. However, it is not optimal in all cases because it is affected by casino rules and the number of decks used. In addition, the expected value of this basic strategy is based on the assumption that all other cards (cards that are not currently used in the game) remain in the mountain. For example, if all the aces are visible, It is not preferable to double down the point hand.

Table of basic strategies

However, the basic onedeckthat's all,Las VegasThis is the case for rules.

S: Stand, H: Hit, D: Double down (hit if not possible), D (S): Double down (stand if not possible), R: Surrender (hit if not possible)

〇: Split, ×: Do not split (according to the case of hard total), △: Depends on the possibility of double down after split (split if possible, not if impossible)

TaiziBe sure to take that action.If you can't remember the fine print, or depending on your mood, you can use the action in parentheses (super-simplified strategy).

handDealer face up card
Total of hard (when there is no A counting as 11)
16SHR (H)RR (H)
15HR (H)H
12H (S)S
9H (D)DH
Total of software (when there is A counting as 11)
A, 8-10S
A, 7S (D)D (S)S (H)H
A, 6H (D)DH
A, 5H (D)D
A, 4H (D)D
A, 2-3H (D)D
A, A *H (D)D
A, A 8,8〇
9,9〇×〇 (×)×
7,7*〇〇 (×)×
2,2 3,3△ (〇)〇〇 (×)×
6,6△ (〇)〇×
4,4×△ (×)×
5,5 10,10×

* If you cannot split.Usually split.

* Depending on the rules, the dividend may jump at 7,7,7 of 21, so there is also an option of double down.

Applied strategy

The basic strategy is based on the assumption that all the decks remain. However, in casinos that do not take counting measures, do not return the cards that have been dealtDiscard trayLeave it in a tray called. Normal,ShoeBy using multiple sets (deck) of lumps called, the game progresses multiple times by this procedure. In a non-shuffled casino, there will be variations in the cards remaining at one point in the game on one shoe. In terms of information theory, ShoeMemorable sourcesIs. Therefore, the combination of the remaining cards causes the player to have an advantage. Here is,Memoryless information sourceThis is a big difference from casino games that do not use cards such as craps and roulette that use dice.

Simulation and theoretical analysis often show player advantage when there are many 10-point and A cards remaining in the remaining deck, and dealer advantage when many 4,5,6 etc. cards remain Have been confirmed by. In addition, there are cases in which play that differs from the basic strategy is optimal. For the sake of explanation, we describe two very artificial situations.

Example 1 When all the remaining cards are 8
The player is at the stage when two 8 are dealt,standTo do. Two 8s are also distributed to the dealer, and it becomes 2, but by the rule the dealerhitMust. As a result, the dealer is dealt 8 of 3bustAs a result, the player will always win. In this case, you always win, so it is optimal to make your stake as large as possible. Also (for explanationSplitIs a rule that isn't allowed)hitWithoutstandDoing is the best strategy.
Example 2 When all the remaining cards are 6
According to the rules, the dealer always changes 6 to 3 for 18 cards.Therefore, the player sees the dealer's 6 and follows the basic strategy against his two 2's.standIf you do, you will always lose. So unlike the basic strategyhitdo. As a result, both players and dealers will be 18, so it will always be a draw. Therefore, this situation does not favor the player or the dealer. However, in order not to losehitTo do so is strategically required.
Example 3 When all the remaining cards are 3
According to the rules, the dealer always makes 3 to 6 with 18 cards.Therefore, if the player plays according to the basic strategy, when 3 becomes 5 of 15 cards,standYou will do, but you will lose.So unlike the basic strategy, until 3 becomes 7 of 21hitIf you do, the player will definitely win.However, in order to win, until the player reaches 21hitIt is strategically essential to do so.

In very simple situations like the above two cases, you can immediately judge whether the player has an advantage or not, and judge the optimum tactics. But in a more general situation, it is very difficult to remember all the cards dealt first. And even if you had a perfect idea of ​​the rest of the card situation, you would still need to count the probabilities in all possible cases to calculate whether the player had an advantage and what strategy to take. So it's very difficult to calculate this with the human head[4].. In this way, it is possible to "approximately" determine the player's advantage or disadvantage and the optimum strategy according to the remaining cards. This isCard countingThis is a method called (card counting).

Hi-Lo, which is a typical counting method, is shown here. First, set the count value to 0 at the beginning of shoe distribution. As the card opens

  • If you see a high card (10-point card and A) -1
  • +2 if you see a low card (6-1 cards)
  • 0 for other cards

The count is increased or decreased according to the rule. Here, if the count exceeds a certain threshold value, it is determined that it is advantageous to the player and the bet is increased to play aggressively. On the contrary, if the count is less than a certain threshold, the player is judged to be disadvantageous and the bet is decreased to be negative. Play like. Also, strategy changes (both strategy changes and index changes; deviations from the basic strategy) are performed based on this count value. However, even if the count value is the same, it is considered that the smaller the number of remaining cards is, the more biased the cards are, so the above count value is divided by the number of remaining cards (or the number of decks) to normalize. The "true count" is used.

By using such a counting, there is a possibility that the player can fight in an advantageous manner. Counting is only an approximate method, so if you perform rigorous calculations, there are situations where the player is disadvantageous even if the count is significantly positive, and conversely the player is advantageous even if the count is negative. It is possible. For example, in Example 1 above, all the remaining cards are 8, which means that the cards that count as -1 and the cards that count as +1 are exhausted at that point, so the count value has also returned to 0. .. Therefore, from the count value, it is judged that this situation is neither advantageous nor disadvantageous. Nevertheless, in reality, the player is overwhelmingly advantageous, so in this case, the Hi-Lo count is making a "wrong judgment".

Therefore, as an index of counting efficiency, it is possible to consider the probability that a strictly advantageous situation is determined to be advantageous. This isBetting correlationIt is called (Betting Correlation) or Betting Efficiency. In the counting method with the same level of complexity as Hi-Lo,Betting correlationIndicates a high accuracy of 90% or more. In other words, it has the ability to judge the advantage or disadvantage of the player with a fairly high probability.

On the other hand, the probability that a certain counting points out the correct play isPlaying correlationIt is called (Playing Correlation) or Playing Efficiency.Playing correlationIs usually not very high, and the limit value is said to be around 70%.

However, these indicators are a measure of the performance of a certain counting method, and to what extent the player becomes advantageous,

  • How many cards remain to be shuffled (also called penetration)
  • How wide is the bet spread?
  • How much do you remember the count value that is the threshold for strategy change?
  • Number of decks, existence of detailed rules

Etc. Data collections, simulation software, etc. for determining this can be purchased at specialized shops.

In general, complex methods can be expected to increase efficiency even more, but with memory and fatigueTrade offBecomes Therefore, there are several types of counting methods depending on the difficulty level and points to be noted.

A typical technique that is as complex as Hi-Lo is

Method that does not require the operation of changing to true count
Hi-Opt I
In addition to the main count, by counting the number of A separatelyBetting correlationMethod aimed at improving


In addition, it is aimed at improving performance by changing the weight when counting, depending on the type of card (for example, count 5 as plus 1 or plus 2 instead of counting as plus 3).Omega II, Zen and so on. These strategies are distributed in books and websites for a fee or free of charge, and strategy magazines such as Blackjack Forum are also published.

In addition, at one timePocket computerSome people use counting to accurately count all appearing cards, and to accurately calculate expected values ​​after that, making it ideal for play in situations other than a clog. Of course, there are currently no houses that allow such equipment to be brought in.

Since earning the public's attention to the effectiveness of counting by the famous Dr. Edward Thorpe's "Beat the Dealer", earning income from counting becomes a regular business.Card counterAppeared very often. Japanese AmericanKen EustonIs also one of the great card players. In the 1970s and the end of the 20th century, card counting was also actively researched. Because of this, the casinoCard counterHas taken various countermeasures to eliminate the.

First of all, legally, there is no law directly prohibiting counting in most parts of the world, and it is impossible to do so, which is a case precedent. In Nevada, where Las Vegas is located, the card counter is fooled by the judgment that "the casino is a private facility, so any third party can be denied entry".

If you shuffle with enough remaining cards, counting revenue will decrease sharply, so you can always encourage this, or specially do it when a person who seems to be a card counter is playing.

Furthermore, in the 21st century, discovering a card counter relied on the human method of observing the pit boss, but by mechanically recording ups and downs of the player's bet and changes in play, pretending to be drunk Even if you are doing camouflage such as playing and playing loosely, or even if the card counter is defeated, a device that correctly determines the skill level of the card counting of that player will be introduced, and you will be able to play large amounts of money. Opportunities for the card counter to make money have decreased significantly. Also,BiometricsA system for identifying threatening players by using is being introduced mainly in places where high-priced bets are made.

Furthermore, the introduction of continuous shuffle machines is being promoted at casinos around the world. If there is a continuous shuffle, card counting has no effect. In addition, games that perform continuous shuffling include players who want to “play by reading the flow of cards” (needless to say, the effectiveness of this technique has not been proven), Players who want to do this (again, of course, the effectiveness has not been proven) will be shunned.

Also, as a measure to simply increase the deduction rate, there is a house that "treats even as a player's loss" (in this case, even money does not hold and even if you give insurance to the hand of Natural 21 and succeed) In order to eliminate the unreasonable feeling due to this, the payout will be refunded in total.In such a house, if the player's natural 21 is established, it is often a rule to immediately pay out regardless of the dealer's hand. ).

In addition, by reducing the width of the betable amount, it is possible to prevent the player from "specially thickening in a game advantageous to the player". Some houses have a minimum amount of money = an upper limit.

in this way,CountingMay allow the player to play mathematically against the casino, and the casino will provide a deduction rate if the player tries to play the basic strategy without counting. Blackjack, which was a rare game that is very low among the games that are played (there is no other game in the casino where the deduction rate is less than 0% under full technical intervention), due to a major rule change At present, it is becoming less attractive and gradually becoming less popular.

Fiction dealing with blackjack

  • Rainman Rain Man (1988)-There are scenes where the characters count in a Las Vegas casino.
  • Crush Las Vegas(2008)-The subject is the actual organizational counting incident.


[How to use footnotes]
  1. ^ Depaulis 2009, pp. 238–244.
  2. ^ In Japanese, the bust is sometimes called "dobon".
  3. ^ If it is not based on the correct judgment, it may be disadvantageous. Please refer to the "Play Guidelines" section below.
  4. ^ RainmanIt is often explained that if you can store all the remaining cards like this, you can play against the dealer in an advantageous manner, but even if you completely store the remaining cards, it is necessary to strictly calculate the probability based on the remaining cards.


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