A catchall tag for school bags used by Japanese students. There are two major styles: the traditional style, which looks like a briefcase, and the modern style, which looks like a small blue shoulder bag.
The traditional style, used by middle and high school students, looks like a briefcase with a rigid flat front and back, and a single large flap that goes over the top with a handle on the top. It may also have a shoulder strap, but this is rarely depicted. Additionally, this style of bag can also have a strap fastened on the back and can be worn like a backpack.
The modern style looks like a small blue sports bag or duffel bag, with a zipper on the top and a strap on each side. The straps are typically big enough to be worn over the shoulder like a shoulder bag, or sometimes on the back like a backpack.