Concentration (card game)

Concentration is a round-based game centered on memory and pattern recognition.

Players work to identify and remove pairs of matching cards from a surface. This game can be played with any number of people in a group. It can also be played alone as a solitaire or patience game. Because it tests mental recall, it is often used as an educational tool. Many people know it by other names, such as Memory, Matching Pairs, or Pelmanism.

Some game shows have even used the name Concentration in their titles.

To begin a standard game, you use a deck of 52 playing cards. These cards are laid face down on a flat surface. Usually, they are arranged in four rows with 13 cards in each row. If you choose to include two jokers, you can create six rows of nine cards each. During a turn, a player selects two cards and flips them face up. The player then checks if the cards form a valid pair. If the cards match, the player takes the pair and plays again. If they do not match, the cards are turned face down. The turn then passes to the player on the left.

Matching rules can change depending on the version being played. In a standard game, a pair must have the same rank and the same color. For example, a six of hearts and a six of diamonds would be a match. However, players can agree to different rules before the game starts. They might decide that any two cards of the same rank match, regardless of color. Alternatively, they might require a match of both rank and suit. The game ends once the last pair has been successfully picked up. The winner is the person who has collected the most pairs.

There are many interesting variations that change how the game feels. The "Any Color" version is helpful for young children because it only requires matching ranks. In the "Zebra" version, players must match the same rank but opposite colors. This means a seven of diamonds would match with a seven of clubs. The "One Flip" variation adds a challenge by preventing a player from going again after a match. For a much longer challenge, players can use two full decks. In a two-deck game, pairs must be identical in both rank and suit. A "Two Decks Duel" splits the field so two players work on separate decks.

Some players enjoy more creative layouts for their cards. In the "Fancy" version, cards are not in a strict rectangular grid. They might be arranged in circles, triangles, or diamond shapes. The "Spaghetti" version involves scattering the cards randomly across the floor. There is also a "Double Decker Checkerboard" style for two-deck games. In this version, players use decks with different colored backs. They lay the cards in a checkerboard pattern of red and blue. This helps players identify card positions and makes the game slightly easier.

A specific version called Pexeso uses a unique set of 64 square cards.

These cards are laid out in an 8x8 square grid. Instead of traditional playing card values, they feature 32 pairs of identical images. These images can be anything from cartoon characters to historic monuments. Pexeso is a great example of how the game can be themed for different interests. A player with a very strong memory could even play Pexeso while blindfolded. In that case, an opponent would have to describe the cards to them.

Playing Concentration alone offers a way to test mathematical strategy. When playing solitaire, you can track your score using poker chips or marks on paper. The goal is to clear the board using the fewest number of turns. Mathematicians have studied the expected number of moves for these games. For a standard 52-card deck, the expected number of moves is approximately 28. If a player has perfect memory and an optimal strategy, they can improve their results. This connects a simple card game to the complex world of probability and information theory.