<![CDATA[Indigenous cultural practices in eastern Indonesia, particularly West Papua, remain underrepresented in ethnomathematics research. This study examined ethnomathematical ideas embedded in the Tumbu Tanah Dance of the Arfak people, focusing on geometric, rhythmic, and symbolic patterns manifested through embodied cultural practices. Guided by D’Ambrosio’s ethnomathematics framework and Indigenous epistemological perspectives, this qualitative ethnographic study employed participant observation, semi-structured interviews with twelve cultural elders and master performers, and visual and kinematic documentation. Data were analyzed using thematic, geometric, and movement analyses to identify mathematical ideas in the dance’s choreography, rhythm, and social organization. The findings identified three principal formations: jey/srem (linear), ikrop (semicircular), and nimot (circular), which demonstrate geometric ideas related to symmetry, rotation, curvature, and spatial proportion. Rhythmic foot-stamping patterns reflected periodicity, recursive sequencing, and temporal synchronization, while dancer arrangements based on kinship and ceremonial roles reflected grouping, partitioning, and numerical distribution. These mathematical ideas are transmitted through embodied movement, communal participation, and intergenerational cultural practices rather than formal mathematical notation. The study demonstrates that Tumbu Tanah constitutes a culturally situated context for recognizing mathematical ideas within Indigenous knowledge and offers potential for culturally responsive mathematics education and cultural heritage preservation.]]>
