My fields of interest include dark matter, axions, neutrino physics, and proton decay. My research comprises of two experimental approaches based on the energy scale of signals. The first approach involves the use of a liquid xenon scintillator that is sensitive to an energy scale ranging from sub-keV to MeV. The XMASS detector with 1 ton of liquid xenon is used to study dark matter particles, axions, and rare decay of xenon nuclei. To discover if dark matter is an elementary particle, we are searching for any deviations of observed events from background expectations, in addition to search for events caused by WIMPs or their relatives. The second approach involves the use of Super-Kamiokande, a large water Cherenkov detector. The hierarchy of neutrino masses and CP violation in the lepton sector may be crucial for understanding the existence of matter in the Universe, and an observation of proton decay clearly indicates a large framework of particle physics. We are working to realize a much larger detector, the Hyper-Kamiokande, which will have a sensitivity far beyond that of Super-Kamiokande. I would like to work together with the members of Kavli IPMU to achieve big discoveries.