The announcements are fairly plain, but they unmistakably emphasize nothing was imported.

…researchers succeeded in developing a quantum computer entirely from domestically sourced technologies, including the dilution refrigerator, control device, superconducting qubit chips, and quantum cloud software. This proves that Japan possesses all the technologies necessary to build its own quantum computers and can integrate them into a system.

The Quantum Information and Quantum Biology (QIQB) team announcing this was launched in 2018 and has less than 100 researchers, yet it is considered the largest quantum centre in Japan.