Editing Card counting (section)

== Back-counting ==
{{More citations needed section |date=June 2021}}
Back-counting, or "Wonging", consists of standing behind a blackjack table and counting the cards as they are dealt. [[Stanford Wong]] first proposed the idea of back-counting, hence the name.<ref>Schlesinger (2005)</ref>

The player will enter or "Wong in" to the game when the count reaches a point at which the player has an advantage. The player may then raise their bets as their advantage increases, or lower their bets as their advantage goes down. Some back-counters prefer to flat-bet, and only bet the same amount once they have entered the game. Some players will stay at the table until the game is shuffled, or they may "Wong out" or leave when the count reaches a level at which they no longer have an advantage.

Back-counting is generally done on shoe games, of 4, 6, or 8 decks, although it can be done on pitch games of 1 or 2 decks. The reason for this is that the count is more stable in a shoe game, so a player will be less likely to sit down for one or two hands and then have to get up. In addition, many casinos do not allow "mid-shoe entry" in single or double deck games which makes Wonging impossible. Another reason is that many casinos exhibit more effort to thwart card counters on their pitch games than on their shoe games, as a counter has a smaller advantage on an average shoe game than in a pitch game.<ref>{{cite web |title=How to Use Frequency Distributions to Determine Your Card Counting Win Rate and Fluctuations |url=http://www.blackjackforumonline.com/content/6DeckText.htm |access-date=20 March 2009 |publisher=Blackjackforumonline.com |archive-date=28 March 2009 |archive-url=https://web.archive.org/web/20090328172315/http://www.blackjackforumonline.com/content/6DeckText.htm |url-status=live }}</ref>

=== Advantages ===
Back-counting differs from traditional card-counting in that the player does not play every hand they see. This offers several advantages. For one, the player does not play hands without a statistical advantage. This increases the total advantage of the player. Another advantage is that the player does not have to change their bet size as much (or at all). Large variations in bet size are one way that casinos detect card counters.

=== Disadvantages ===
Back-counting has disadvantages, too. One is that the player frequently does not stay at the table long enough to earn [[comps (casino)|comps]]. Another disadvantage is that some players may become irritated with players who enter in the middle of a game. They believe that this interrupts the "flow" of the cards. Their resentment may not merely be superstition, though, as this practice will negatively impact the other players at the table; with one fewer player at the table when the card composition becomes unfavorable, the other players will play through more hands under those conditions as they will use up fewer cards per hand. Similarly, they will play fewer hands in the rest of the shoe if the advantage player slips in during the middle of the shoe, when the cards become favorable; with one more player, more of those favorable cards will be used up per hand. This negatively impacts the other players whether they are counting cards or not. Also, a player who hops in and out of games may attract unwanted attention from casino personnel and may be detected as a card-counter.

=== Group counting ===
While a single player can maintain their own advantage with back-counting, card counting is most often used by teams of players to maximize their advantage. In such a team, some players called "spotters" will sit at a table and play the game at the table minimum, while keeping a count (basically doing the back "counting"). When the count is significantly high, the spotter will discreetly signal another player, known as a "big player", that the count is high (the table is "hot"). The big player will then "Wong in" and wager vastly higher sums (up to the table maximum) while the count is high. When the count "cools off" or the shoe is shuffled (resetting the count), the big player will "Wong out" and look for other counters who are signaling a high count. This was the system used by the [[MIT Blackjack Team]], whose story was in turn the inspiration for the Canadian movie ''[[The Last Casino]]'' which was later re-made into the [[cinema of the United States|Hollywood]] version ''[[21 (2008 film)|21]]''.<ref>Axelrad (2010), pp. 19, 259.</ref>

The main advantage of group play is that the team can count several tables while a single back-counting player can usually only track one table. This allows big players to move from table to table, maintaining the high-count advantage without being out of action very long. It also allows redundancy while the big player is seated as both the counter and big player can keep the count (as in the movie ''21'', the spotter can communicate the count to the big player discreetly as they sit down). The disadvantages include requiring multiple spotters who can keep an accurate count, splitting the "take" among all members of the team, requiring spotters to play a table regardless of the count (using only basic strategy, these players will lose money long-term), and requiring signals, which can alert pit bosses.

A simple variation removes the loss of having spotters play; the spotters simply watch the table instead of playing and signal big players to Wong in and out as normal. The disadvantages of this variation are reduced ability of the spotter and big player to communicate, reduced comps as the spotters are not sitting down, and vastly increased suspicion, as blackjack is not generally considered a spectator sport in casinos except among those actually playing (unlike [[craps]], [[roulette]], and [[Big Six wheel|wheels of fortune]] which have larger displays and so tend to attract more spectators).