Concentration

1 9 5 8 - 1 9 7 3 (USA)

Concentration was NBC's longest running game show. In addition to its fourteen year daytime run, there were also  two primetime versions, a four week run in 1958 with host Jack Barry and a five month run in 1961 with host Hugh Downs.  

There was also a syndicated version which ran from 1973 to 1978 with host Jack Narz. Two players took turns to call out a pair of numbers (from one to thirty), which appeared on a three-sided wedge on a game board.

If the prizes (or information such as "forfeit one gift" or "take one gift") matched, the player was credited with the prize. The third part of the wedge was shown when a match was made, and revealed two portions of a slowly building rebus puzzle.

The player was given a chance to guess the answer and if correct, would win the game and all the prizes. If not, they called out two more numbers and tried to make another match. When the player failed to make a match, the turn went to the opposing player. 

The winning player continued to play against other challengers until defeated or until they won 20 games.