Instructional materials that integrate students' cultures make teaching and learning relevant to students. However, there is a lack of culture-based and research-based teaching resources in mathematics that are deemed pertinent to Kalinga's full-modular learning and cognizant of the framework for Philippine mathematics teacher education's principle on realistic mathematics. As such, this study aims to recontextualize the Kalinga tribe's "batek" and "laga" into an Ethnomathematical Teaching Resource (ETR) through the Second Generation of Didactical Engineering (SGDE). Nine elementary teachers and two teacher-trainers participated in the preliminary phase, which was arranged into an ethnomathematical study, first teacher interview, and pretest. These were the basis of the design and a priori assumptions organized into Teaching Strategies (TS), Mathematical Content Knowledge (MCK), and appropriateness test. Subsequently, the realization phase tested the assumptions by administering the ETR, second interview, Communication Index (CI), and post-test. As a result, the a posteriori analysis and validation showed that teacher participants' exposure to the ETR provided potential TS, improved their MCK, and made appropriate to their level. Consequently, the recontextualization process of the cultures described in the study strengthens the awareness and responsibility of the Kalinga teachers to their cultural community. This also contributes to the preservation of the practices.