A disclosed system includes electronic tags and a communication apparatus that communicates with the electronic tags and includes management information to manage the electronic tags. In the disclosed system, each of the electronic tags contains an ID a part of which represents one of group IDs identifying groups among the electronic tags and is configured to send a response when a request sent from the communication apparatus contains a corresponding one of the group IDs; and the communication apparatus is configured to send requests one by one each of which requests contains one of the group IDs, thereby to request the electronic tags group by group to send responses to the communication apparatus, and to recreate the management information based on the responses.