Tokyo Tech has started the operation of brand-new TSUBAME3.0 supercomputer, which got World No. 1 in the Green500 in June 2017. It provides the peak performance of 12PFlops with 2,160 NVIDIA Tesla P100 GPUs. Not only as a "post-peta" supercomputer, it has been designed as a "big-data" supercomputer with 16PB shared storage and high-speed NVMe Flash SSDs, whose total performance exceeds 1PB in capacity and 1TB/s in access speed. We will demonstrate our R&D efforts including big-data architecture and software, ultra-green cloud system operation, advanced cooling and post-petascale applications.