Sinopsis
Japan has entered a new era called "Reiwa," after moving past the Hesei Era on April 30th 2019. It is in this era, past the time of people like the legendary Shigeru Akagi and others like him who gambled on mahjong for a living, that a new gambler has arisen known only as "Yami-ma no Mamiya."
(Source: MangaDex)