Ever since OpenPeppol and the E-invoice Promotion Association (EIPA) decided to use Peppol International Invoicing Model (PINT) as a Japanese e-Invoicing standard which is the international version of Peppol based on BIS Billing 3.0 Japan is in the progress of adopting PINT. The mechanism of Peppol is based on the 4 corner model which requires service providers for access points. In July 2022, the accreditation process started for Peppol Certified Service Provider by the Japan Peppol Authority. Lately, SNI has become one of the service providers in Japan according to the official announcement.
You can access the full updated list of service providers here