Don Casey, former coach of the New Jersey Nets and L.A. Clippers, has often contributed to NBA.com's "Coach's Corner" series. He recently completed a book, Own the Zone: Executing and Attacking Zone Defenses and is currently working on zone concepts with Team USA. Presented below is an excerpt from Casey's book.

Chapter 2
The Evolution of the Zone Defense and Zone Press

Throughout the history of basketball, most defenses were created out of necessity. The constant improvement of individual skills and team offenses forced coaches to experiment with different defensive alignments and strategies. Even the rules favored the offensive team so it has been a continuous battle for coaches to try and keep the offense from getting too far ahead.

IN THE BEGINNING
The only type of defense used during basketball’s first 20 years was a full-court man-to-man defense. A player was responsible for one opponent and followed this player all over the court. When a team lost possession of the ball its players immediately located their assigned opponents and “stuck with them like glue” until the ball was recovered. The game’s founder, Dr. James Naismith instructed defensive players to do everything within the rules to prevent their opponents from getting the ball. This style of defense required a tremendous amount of stamina and energy.

THE FIRST ZONE DEFENSE
The zone defense was invented in 1914 in a game played between Bristol (WV) High School and the Grafton YMCA. The novel defense was created as a remedy for a slippery playing surface caused by a leaky roof. During the first half, the court became so slick that players spent much of the time slipping and sliding. Future Hall of Fame coach Clair Bee was a player on the Grafton YMCA team. “I remember the game distinctly,” said Bee. “It was the first time in my life that I ever played with older fellows. The reason that I played was the floor was so slippery in the first half and I was the only one who could stand up.”

At halftime Cam Henderson, coach of the Bristol team, designed a strategy that became the first zone defense. “I told the boys there was no point running after those boys from Grafton, when they got the ball,” said Henderson. “We’d just stand still. I went out there and showed them how to line up. There were three boys out front and two back. It worked out just fine on that wet court.”


Areas of Responsibility

CAM HENDERSON: THE ARCHITECT OF THE ZONE DEFENSE
Cam Henderson was fascinated with the potential of his new defense and it became a mainstay during his illustrious coaching career at Bristol High School, Muskingum College, Davis & Elkins College, and Marshall University. Henderson’s innovative mind revolutionized the game by combining the zone with a fast break. He portrayed the zone defense and fast break as “twins,” with the zone being born first, followed by the fast break. Clair Bee said that Henderson’s 1938 squad was the best that he had even seen in transition from a zone defense to a fast break offense.

The original zone used by Henderson was a 3-2, but he soon discovered that it did not provide the necessary rebounding to support his fast break offense. Cam’s solution was to drop one of the front defenders back, creating a 2-3 alignment. Henderson positioned the team’s best dribbler on the front line and assigned him to be the middleman on the fast break. The other front line defender filled the outside lane on the right side. It was essential that this player was proficient at making right-handed lay-ups. Henderson required that lay-ups were executed with the body between the shooting hand and the basket. A player from the back line filled the outside left lane.

Henderson preferred this player to be left-handed. The middleman was instructed to dribble down the center of the floor and if unguarded, shoot the ball. If defended, the ball handler looked to his teammate filling the right lane. If this player was defended, the ball was passed to the player filling the left lane.


Initial Alignment

Henderson demanded that the players filling the outside lanes sprint to the basket. In the early gymnasiums, the baskets were mounted on the walls at the end of the court and most facilities did not even have pads attached to the walls. The safest thing for a player to do was to slow down so that he did not run into the wall. But with the determination that Henderson required of his teams, this option was not acceptable. Henderson’s players pursued the basket without regard to their own personal safety, which often resulted in a two-on-one or a three-on-two situation.

There were many unforgettable games during Henderson’s illustrious career. One of them occurred in 1938 when Marshall upset Long Island University and snapped the Blackbirds 40-game winning streak. Another took place in 1947 when Henderson led Marshall to the National Association of Intercollegiate Athletics (NAIA) national championship with his zone defense and fast-break offense.

THE ZONE DEFENSE IN PROFESSIONAL BASKETBALL
It took less than two months for the owners in the newly formed Basketball Association of America (BAA) to decide that they wanted no part of the zone defense in their league. The St. Louis Bombers, one of the top teams in the BAA, used a zone defense so successfully that the owners called for a special meeting on January 11, 1947 and voted to prohibit the use of the zone defense. Their reason was that zones were “too effective” in holding the score down which would hurt fan interest and gate receipts.

In 1949 the BAA merged with the National Basketball League (NBL) and formed the NBA. The NBA continued with the ban on zone defenses until 2001. Jerry Colangelo, one of the most innovative and influential owners in NBA history, believed the approval of the zone defense by the NBA was one of the most significant moves since the implementation of the 24-second shot clock in 1954. “This is a bold move on the part of the NBA to allow something to take place that for years we’ve been hiding from.” Colangelo said. “We feel confident this will enhance the game.”

The NBA rules regarding the zone defense are different than the ones used in college and high school basketball. In the NBA, a defensive 3-second rule prohibits a defensive player from remaining in the lane for more than three seconds without closely guarding an offensive player.

Many basketball experts believe that the addition of the zone defense in the NBA has allowed coaches more flexibility and augmented their tactical opportunities. Hall of Famer Joe Dumars, president of basketball operations for the Detroit Pistons, believes the zone defense has a definite place in the NBA and that more and more teams will begin utilizing the zone in the future. Prior to the 2007 season, head coach Flip Saunders predicted that the Pistons would use a zone defense at least 10 to 15 percent of the time.