Recently I attended an event that showed me a mass of `sine wave` patterns on display, which in turn prompted me to write this article. Many students simply don't understand the relevance of pattern practice, either why they do it, their purpose or what techniques are for! General Choi stated in his manual, under the section ` Essential Information ` with regards to patterns, that: 7. Students should know the purpose of each movement. 8. Students should perform each movement with realism. This article is not to discuss individual techniques contained within patterns (no 7), although a few might be highlighted within the context of this article, but to hopefully enlighten a few students as to `why we practice patterns`! However, the total, overall practice of patterns falls with no.8: Students should perform each movement with realism, and thus their pattern which of course contains 'each movement'! In this new era of three main ITF groups & many more independent Chang-Hon Taekwon-do schools there are now three main variations on the ITF tuls (when I refer to ITF I am not referring to any organisation, but to the style of Taekwon-do, ie. Chang-hon, which is mostly referred to as 'ITF style' whether correct or not) These three main variations can be seen as: 1.Very old, almost Karate type performance - emphasising lots of hip twist, off-turned shoulders & no knee-spring or sine-wave motions 2.Original, emphasising both hip twist & knee spring, but not sine-wave per se. 3.New, emphasising little or