Our team r3kapig provided 10 challenges (out of 13 total) for the recently concluded Baidu CTF, one of the DEFCON qualifier competitions, and served as the chief referee to control the competition format, some rules, and challenge quality. Baidu CTF is a new qualifier competition, and we also made some attempts, such as having AEG teams compete against top human teams in the same competition. Although some minor issues arose during the innovation process, we still contributed a qualified qualifier competition through everyone's joint efforts. Today, I want to use this competition as an opportunity to discuss my personal understanding of CTF challenges.