We aimed to extend instance theory into the domain of real-world professional vision development, examining the effects of explicit rules and exemplars on development of professional vision in a randomized controlled fashion. Participants were novice therapists (N = 48) attending accredited clinical psychology programs in Japan and were randomly divided into four training groups, which received (1) declarative knowledge-based and exemplar-based training, (2) declarative-based training only, (3) exemplar-based training only, and (4) no training. Before, during, and after the training, participants watched an authentic solution-focused brief therapy (SFBT) video and had five minutes to write down their notices regarding the video. Three expert therapists independently evaluated these notices in terms of relevance to SFBT. As hypothesized, novices who received both types of training showed increases in notice relevance during and after the training. In contrast to our hypothesis, novices who received exemplar-based training only showed increased notice relevance during the training. Declarative knowledge with exemplars could provide the best approach for the development of professional vision. Still, many self-motivated learners might learn professional vision in the absence of explicit teaching of declarative knowledge. Future studies should examine the link between participants’ motivation and training effects of mere exposure to exemplars.