During June 2025, Kaminaka focused on enhancing data quality and documentation clarity for the jami-fhir-jp-wg/jp-core-v1x repository, targeting FHIR interoperability improvements. Kaminaka addressed two key bugs by correcting JP_Patient data definitions and standardizing postal code formatting, ensuring alignment with FHIR standards and improving data validation. Additionally, Kaminaka clarified the nameRepresentationUse documentation to better support multilingual data, including romanized, kanji, and kana notations. Working primarily with FSH and Markdown, Kaminaka emphasized clear commit messages and thorough documentation updates, which improved traceability and onboarding. The work demonstrated careful attention to detail and contributed to smoother integration with external systems.