If the Tonegawa anime is supposed to be a prequel to Kaiji that is set in the 90s, how come it features modern things?


_Mr. Tonegawa: Middle Management Blues_ is supposed to be a prequel to _Kaiji_
series that is set in the 90s. However, the anime features modern things, for
example: smartphones, vaping, apps like Yelp.

How come such things exist in the series?

