Badminton is a growing sport with a limited amount of expertise both in players and coaches so attempts are being made to extend the expertise internationally. The purpose of this study is to gain an understanding of coaching expertise in badminton because such an understanding might have implications for a more general understanding of expertise, problem-solving, situated learning, and coaching, for the design and development of coach education, and for the acceleration of skill acquisition in the sport. Six badminton coaches working with world class players were studied ethnographically. Research was conducted by observing, interviewing, and traveling with the team and coaches in Germany, Spain, and Malaysia. Data was analyzed through an emergent coding process used to identify themes. A preliminary model of expertise was developed directly from the codes. This model was then compared with a variety of models in the literature on coaching expertise. A final model with constructed as a result of interplay between data and published theories. The resulting model helps to capture coaching expertise in its very subtle aspect. In addition to this model, this study examines the roles of cultures, personal life experiences, and politics in the lives of these six coaches. Important differences were found between new coaches and coaches who have many years of experiences. Findings also suggest ethnographic method for studying subtle expertise that requires longer involvement in natural setting due to the nature of expertise. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]