For those who love the anime/manga, this is something that may have passed people by.
Here’s a brief description of where the story takes place compared to the anime/manga.
“Tokyo, 1958. A man seriously gambles at a mahjong parlor. He’s playing against members of the Ryuzaki yakuza clan. If he loses, he must pay his debt through his own life insurance – truly a game of life and death. With his own existence at stake, he can only play passively, and the game comes to a head. Suddenly, a mysterious boy appears. His name is Akagi, a thirteen-year-old kid. The man senses a strong aura around the youth and decides to have Akagi substitute for him in the next round.”
You can watch the episodes on Crunchyroll, with English subtitles here.
Some region restrictions may apply, depending on where you are in the world.