This is a user friendly course is given to explain the inner workings of a watch. It is a must for anyone considering taking the CW21. It fills in some of the blanks and allows you to understand not only functional issues, but theoretical ones as well. Differences between modern fast beat watches verses their older counterparts will discussed and physical differences will be shown in an enlarged viewing state. Lubrication, Epilame, escapement, isochronism, vertical clutch systems, Automatic systems, calendar systems, basic calculations and much more will be explained. Practical scenarios of things you are likely to encounter, will also be presented and corrective suggestions will be offered. Testing will be done at the end of each section covered. The answers will be reviewed and you will have an opportunity to discuss the bases of questions and the details of the answers. You’re invited to bring your questions to the class.