Five Facet Mindfulness Questionnaire (FFMQ) is a measure of mindfulness that holds an important position in ACT. Many measurement scales for mindfulness have been published in recent years, but FFMQ is the result of joint factor analysis.
The Japanese version of FFMQ has a five-factor structure (observing, describing, acting with awareness, nonjudging, nonreactivity).
Sugiura, Y., Sato, A., Ito, Y., Murakami, H. (2012). Development and validation of the Japanese version of the Five Facet Mindfulness Questionnaire. Mindfulness, 3, 85-94.
Takahashi, T., Saito, J., Fujino, M., Sato, M., & Kumano, H. (2022). The Validity and Reliability of the Short Form of the Five Facet Mindfulness Questionnaire in Japan. Frontiers in Psychology, 13, 833381. DOI: 10.3389/fpsyg.2022.833381
The FFMQ Japanese version is on the ACBS Japan Chapter website.