The borrowed books can be returned to any of the University of Tsukuba Libraries.
When the library is open → to the return counter (main counter)
When the library is closed → to the book-drop (near the library entrance)
However, AV materials (DVDs etc.) must be returned to the main counter of the original library to prevent damage.
If there is a single book which is not returned within the loan period (overdue materials), you are suspended from borrowing, renewals, and reservations.
The overdue penalty period is the same period as the longest overdue period AND until the overdue materials are returned. The penalty period starts from the next day after all overdue materials have been returned.
Your overdue information can be checked on MyLibrary.