The Progress until the Appearance of the Zone Defensein Basketball
　　- From the viewpoint of the developmental process of the　defensive systems -

　　　　　　　　　　　　　Nobuyuki OKAWA (Toyama University)

　　　　　　　　　　　　　　　　　　　　　　Abstract

　　Today we have a great number of defensive systems in basketball. In essence, however,
there are two main types, namely "the zone defense" and "the man-to-man defense".
Although the zone defense was the most important defense, it was not permitted in the
professional organization, N.B.A. (National Basketball Association) until the 2000-01 season.
The purpose of this study is to clarify the progress until the appearance of the zone
defense.
　　　The following conclusions can be drawn.
　1) In the history of basketball, nine, seven, and finally five men have constituted a team.
　　With nine men team, the man-to-man press defense was used predominantly in the full
　　court style. Within five years, five men team became the norm (five men team was
　　ntroduced in 1893), and this made the duties of players diversify. A guard was forced to
　　enter the front court and assist in the scoring. He was called "the running guard".
　2 ) About 1900, there was introduced into basketball a style of defense called "the
　　five-man one line defense". This was a countermeasure to meet the running guard.
　3 ) Shortly after that the defensive strategy was rapidly developed into several new types,
　　namely "the two-man set and three-man shifting defense", "the three-man set and two-
　　man shifting defense", "the four-man box with one-man shifting defense", and "the
　　five-man two-line defense".
　4 ) As the starting position of the five-man two-line defense resembled "the 3-2 zone
　　defense", this defense has often been referred to as "the original zone defense". But this
　　style was still the man-to-man defense.
　5 ) The transition from the five-man two-line defense to the 3-2 zone defense was due to
　　the outnumbering offensive players attacking the rebound-guards. The zone defense has
　　developed from 3-2 zone defense to "the 2-3 zone defense" and then into "the 2-1-2 zone
　　defense". From these basic zone defenses several variations have developed.