Two hours. According to official website's inquiry, the Ministry of Education recorded and broadcast an open class entitled "Ten Thousand Teachers and Students Attend the same National Security Education Class" on April 5, 2023, which lasted for two hours. April 15, 2023 is the eighth National Safety Education Day. The theme of the National Security Education Day is "Implementing the overall national security concept, enhancing the national security awareness and literacy of the whole people, and consolidating the social foundation for ensuring the new development pattern with the new security pattern".