Identification and further motivation of gifted students are widely discussed among the science education community. In the context of the educational system of the Czech Republic, competitions serve as one of the main ways to identify those gifted in precollege education. In this article, we report the foundation of a team-based open-book competition in chemistry. The competition targets upper-secondary-school students with an interest in chemistry. We describe the organizational process of the competition, including the selection and reviewing of questions. We discuss the personal requirements for organizing staff, the need to train them adequately, and various ways of supporting them. We explain the scoring system and discuss the score data from years 2016-2020, assessing the difficulty of the question sets and proposing an optimal difficulty profile. The competition has been held concurrently in the Czech Republic and the United Kingdom since 2020 and has the potential for further internationalization.