Yes, this was a well-known part of the Sakoku policy: https://en.wikipedia.org/wiki/Sakoku https://en.wikipedia.org/wiki/Sakoku Having heard what had happened

Yes, this was a well-known part of the Sakoku policy: https://en.wikipedia.org/wiki/Sakoku https://en.wikipedia.org/wiki/Sakoku Having heard what had happened in much of the rest of Asia, the shoguns were extremely concerned about Christian proselytizing, and this was their extreme but effective way of making it impossible. All local Christian converts were also put to death.