The concept of "bottomless" school uniforms, also known as "pochibangō" or "loose socks," has been a topic of interest in Japan. However, I believe you are referring to "bottomless school" or more accurately, a type of uniform called " Seifuku jūban" or simply 'school patched' which relates more generally to school uniforms.
When you hear "Japanese school" and "patched," it’s often a reference to the rich history of that spans from rebellious 70s delinquents to modern Harajuku "pretend uniform" aesthetics. japanese bottomless school patched
It taps into centuries of Japanese textile history. The concept of "bottomless" school uniforms, also known