Kushikatsu sando is Osaka's deep-fried skewer culture folded into a sandwich. Kushikatsu is the Osaka habit of threading bite-size pieces of meat, vegetables, or seafood onto bamboo skewers, coating them in a fine panko crumb, and deep-frying them to order, eaten with a communal pool of thin sauce and a firm no-double-dipping rule. The sando pulls those crisp morsels off the skewer and lays them between bread with that same sauce, translating a standing-at-the-counter snack into something you can hold and walk with. It is a regional specialty more than a national staple, and it carries the unfussy, fried-and-saucy character of the Osaka stalls into sandwich form.
The craft is keeping a multi-piece fried filling crisp and the bread from drowning. Good kushikatsu has a thin, even, lacy panko shell fried hot so it stays brittle, the interior of each piece cooked just through and still juicy. Building a sando from it means arranging the pieces so the layer is level rather than lumpy, brushing the thin kushikatsu sauce on with discipline so its light sweet-tangy edge seasons without sogging the crumb, and often laying in shredded cabbage for crunch and a cool counterpoint, echoing how the skewers are eaten with raw cabbage at the stall. The bread is usually soft shokupan or a split roll, sturdy enough to carry fried pieces without collapsing. A good one stays shattery and well seasoned with a clean bite; a poor one is the greasy, sauce-soaked version where a tired crumb-coat and too much sauce have flattened everything into mush.
The wider category overlaps the katsu sando family but stays its own thing because of the mixed-skewer character, so versions range across pork, beef, chicken, and vegetable-forward builds, sometimes mixing several in one sandwich the way a skewer run does. The single-cutlet katsu sando and the croquette-based korokke forms are close cousins that read very differently. Each of those deserves its own article rather than being crowded in here.