The emPHasis-10 is a patient-reported outcome measure used to assess health-related quality of life in patients with pulmonary hypertension. The emPHasis-10 was originally developed in English and has been translated into various languages. This project aimed to develop a linguistically validated Japanese version of the emPHasis-10 to make the tool available in Japan. The process used to develop the Japanese version included forward translation, back translation, and cognitive debriefing. Initially, two translators independently translated the original tool into Japanese, taking into consideration the concepts described in the concept elaboration report provided by the original developer. A third translator then reconciled the two translations. Next, the reconciled version was translated back into English by a native English translator. The results were reviewed by the original developer to check concept equivalence. Finally, cognitive debriefing was conducted among 10 patients with pulmonary hypertension. The wording of one item was amended to clarify the meaning, and minor changes were made to improve readability. This translation and adaptation process resulted in a linguistically validated Japanese version of the emPHasis-10.