free-use notebook; blank notebook
A notebook with unruled or blank pages, often used for drawing, scribbling, or free writing. Commonly associated with children's stationery.
Children like drawing pictures in a free-use notebook.
Since a free-use notebook has no ruled lines, you can use it freely.
Compound of 自由 (free) and 帳 (notebook). The term likely originated from the idea of a notebook that can be used freely without the constraints of ruled lines.