Electronic musical score apparatus

An electronic musical score apparatus comprising at least two display units connected to each other to be openable and closeable, wherein

• the at least two display units includes:
• a memory configured to store musical score page data and an application program;
• display portions provided respectively in the at least two display units, the display portions configured to display images based on the musical score page data and allow a user to make a writing on the display portions;
• a controller configured to control image display in the display portions of the display units;
• and
• a communication portion configured to perform data communication with an external apparatus based on the application program in response to an instruction from the controller,
• the electronic musical score apparatus is capable of converting the writing made by the user into first annotation data, associated with the musical score page data but being manageable separately from the musical score page data, and of causing the first annotation data to be stored, and
• when the electronic musical score apparatus displays an image of the associated musical score page data together with an image of the first annotation data on the display portions and then the user rewrites the first annotation data, the electronic musical score apparatus is capable of providing a write history for the first annotation data by causing the first annotation data before the rewriting to be stored as first-generation first annotation data and causing the first annotation data after the rewriting to be stored as second-generation first annotation data.