I study the beginning and an end (if any) of the Universe using the laws of physics and state-of-the-art measurements. I spend 2/3 of my time on theoretical research, and remaining 1/3 on providing theoretical underpinnings to experiments, and analysis and interpretation of the new data. My main weapons are the cosmic microwave background (CMB) and the large-scale structure of the Universe. I was a member of the Wilkinson Microwave Anisotropy Probe (WMAP), with which we determined the age and composition of the Universe. We also found strong evidence for cosmic inflation by discovering adiabatic and Gaussian super-horizon fluctuations that are nearly, but not exactly, scale invariant. Over the next decade I would like to find definitive evidence for inflation by measuring B-mode polarisation of the CMB, rule out the standard cosmological model (ΛCDM) by mapping cosmic structures up to a redshift of z=3.5, and determine the mass of neutrinos. To this end I am co-leading two galaxy surveys with the Prime Focus Spectrograph (PFS) on the Subaru telescope led by the Kavli IPMU, and with the Hobby-Eberly Telescope in the McDonald Observatory. For CMB, I am a member of the LiteBIRD team, and I am leading a team investigating impacts of the Galactic foreground emission on B-mode polarisation. I also enjoy thinking about what new physics we can learn about inflation in case of the discovery of primordial gravitational waves.