My current research interests are in the field of observational cosmology, especially on the properties of dark energy and inflation at the very early universe. The first light of the Hyper-Suprime Cam at the Subaru Telescope is around the corner. The HSC wide field imaging survey is aimed at exploring the properties of dark energy, by measuring the shape of more than 250 million galaxies most precisely and computing the shear fields due to the weak gravitational lensing. I am also involved in a small satellite project called LiteBIRD, which detects the primordial B mode polarization of the cosmic microwave background arising from the gravitational waves from the primordial tensor fluctuation generated by the inflation. Until several years ago, I had worked on the Belle experiment at the High Energy Accelerator Research Organization (KEK), which studied the properties of the CP violation in the B meson system. We have experimentally“ proven the Kobayashi Maskawa theory.” I think the dark energy and the“ particles” which cause the inflation are the subject of particle physics. It is quite intriguing that we can pursue research using the good old experimental techniques of high energy physics.