In Japan, sparked by the 2013 "Workshop on Ultra-Low Background Subatomic Physics," this field has steadily evolved through consecutive research areas: "Revealing the History of the Universe with Underground Particle and Nuclear Research" (2014–2018), "Unraveling the History of the Universe and Matter Evolution with Underground Physics" (2019–2023), and the currently ongoing project launched in 2024, "Investigation on the Origin and Evolution of Matter in the Universe by Extremely Rare Events." Concurrently, research teams at the Kamioka underground facility collaborating on projects such as neutrinoless double-beta decay and dark matter have formed a unified Japanese ultra-low-background underground particle physics community, thereby promoting research at the Extremely Rare Phenomena Frontier.

We recognize that this frontier will remain a crucial methodology in particle, nuclear, and astrophysics for decades to come. To ensure its continuous advancement, the growth of the entire community—including the preservation of ultra-low radioactivity techniques and human resource development—is indispensable. The “Kamioka Extremely Rare-phenomena and NEutrino-research Laboratory (KERNEL)” has been newly established to address these exact needs. Driven by the dual engines of research and technology, KERNEL will spearhead the community and lead the world at this frontier. While initially operated by the Research Center for Neutrino Science (RCNS) at Tohoku University and the Research Center for Nuclear Physics (RCNP) at Osaka University, it aims to evolve into a broader consortium with wide-ranging participation from related institutions.

We look forward to welcoming many researchers from both Japan and abroad, as well as the young talents who will lead the future of our field. Let us join forces here in Kamioka to challenge and unravel the mysteries of the Universe and elementary particles together!