The authors examined the process of change in size comparison strategies among preschool-age children. Twelve 5- and 6-year-old children were provided with origami exercises and size comparison tasks for 5 days consecutively, and another twelve 5- and 6-year-old children received size comparison tasks only. Children's strategies for the size comparison tasks were analyzed in terms of placement and adjustment. In contrast with the children in the control condition, the children who were provided with exercises in origami increased their use of superimposition and adjustment strategies by 2 dimensions across the 5 days. The authors argue that origami exercises helped the children connect their implicit understanding of relative size with the use of more effective strategies for size comparison.