This study investigated the learning process of preservice elementary teachers (PSTs) through lesson study in a mathematics teaching methods course. Lesson study meeting data of kindergarten PSTs were analyzed to examine the shifting focus on (1) student collaboration in classroom (vision), (2) teaching practices (making content accessible), and (3) understanding of student thinking of mathematics, in teachers' talks. The four learning phases were identified in which the PSTs' vision guided sense-making process, and lesson study provided the structure for the process. Visions can support or distract PSTs' learning, and learning experiences should guide PSTs to understand how to enact their visions in relationship to classroom practices.