5 Values
The Japanese version of Wikipedia says there are 19 specific practices, while the English version says there are 12.
The number has increased to 19 after several revisions, and is now classified into four categories according to the position of the subject
English Extreme programming practices - Wikipedia
Ron Jeffries 11/08/2001
https://web.archive.org/web/20061215120657/http://www.xprogramming.com/xpmag/whatisxp.htm
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