Yuba Isukari’s 2016 Yokohama Station SF was originally published as Yokohama Eki SF, with illustrations by Tatsuyuki Tanaka. The 2021 translation is by Stephen Paul.
Replicating endlessly, Yokohama Station has spread across Honshu. Life for Insiders — children under six and people over six who have implanted Suika chips — is tolerable. Necessities of life are provided as long as the Insiders do not violate the automated turnstile’s inflexible rules. It’s no utopia but life could be much worse.
Just ask anyone from the Ninety-Nine Steps.