This Mahjong Prodigy Is So Nihilistic

With no warning, and no idea how it happened, I arrived in this world as a ghost with flesh and blood, drifting through the corners of Tokyo. My name for now is Minazuki Tetsuya. I survive by playing mahjong in Tokyo, living in constant fear as I wait for the final hand that will take everything from me. Until... I met Tenmu Koro. So, is this the Kobayashi Ritsu universe? Never mind, that's not especially important...