As pressure is applied in a chess position, tension is developed. Proper application and control of tension is crucial in the outcome of the struggle. This pioneering study analyzes the types of chess tension and provides carefully selected examples to permit the player to recognize these situations in his own games. Improvements in the handling of tension will definitely result in playing better chess. 41 complete games are included to illustrate the development of tension and its effect upon the course of the game. The author points out that the "secret" of Petrosian's mysterious maneuvering was merely patient development of superb tension. The tension in the French Defense is also used to provide full understanding of the concept. The premature release of tension is revealed as a primary cause of the rapid deterioration of superior positions.