Few research studies have been conducted in a primary school in early mathematical education about the teaching of geometry. This research aims to contribute with knowledge of how teachers' awareness and understanding of necessary conditions to enhance students' abilities to discern two- and three-dimensional shapes develop. In this research, qualitative methods were used to analyse data from a lesson study in grade 4 in the subject of mathematics. Data were primarily collected through audio-recorded conversations with teachers before and after the lesson, and the results of students' pre- and post-test. The results of this research showed increased awareness of using collaboration opportunities to apply professional classroom instructions and activities to enhance students' knowledge of two- and three-dimensional shapes. This research elucidates how the practice-based professional development approach emphasised the teachers' teaching targets for understanding students' content knowledge of geometric shapes. Additionally, the result highlighted teachers' awareness and understanding of the challenges students face in learning about three-dimensional shapes from two-dimensional representations. Future research should develop a more iterative and revised research lesson design to develop more powerful content knowledge and classroom activity in this topic area.