Permanent marker on washi tape survives a backpack, mostly

Permanent marker on washi tape mostly stays in a backpack, but it will smudge where it rubs hard.

Washi tape is basically thin paper, so marker soaks in a bit — that’s actually good. A fine-tip permanent marker writes cleanly and won’t immediately wipe off. The problem is friction. Backpacks toss stuff around, and corners or edges of your labeled tape will pick up scuffs that turn your tidy label into a blurry mess.

If you want it to actually last, do one cheap thing: cover the written-on tape with a short strip of clear packing tape or a clear address label. Then the ink can’t rub off, and the washi tape underneath still does its job of being easy to remove later.

This is not where you get fancy. Fine-tip Sharpie, washi tape, clear tape on top, done.