On August 20 and 21, as the part of "Children's Day for Visiting Kasumigaseki" under the auspices of the Ministry of Education, Culture, Sports, Science and Technology, a program "Explore the Biggest Library in Japan" was held in the Tokyo Main Library. 73 children and accompanying adults participated. They visited the underground stack rooms of the Annex to get to know how many materials were stored and various ways in which they were preserved; learned about library services to understand the role of the library: reference services by answering questions modeled on library users' inquiries using dictionaries in the Humanities Room and the Business, Science and Technology Room: "Be a librarian: experience of reference service"; learned about the structure and preservation of books: "Let's look at the book hospital". On August 29, a study tour was held for those who had not been chosen by lot; 28 people participated.