Panko
Japanese breadcrumbs made from crustless white bread, coarse and flaky, that fry up especially light and crisp.
Panko is sold in many larger supermarkets alongside other Asian products, and reliably in Asian grocery shops or online. If you cannot find it, ordinary breadcrumbs will do, though the crust turns out finer, denser and less crisp.
Substitute:
Ordinary breadcrumbs work but give a finer, denser and less crisp crust. Coarsely crumbled, slightly dried white bread without crusts comes closer.