The karaage sando is Japanese fried chicken folded into soft white bread, and it is a different animal from a katsu sando despite the family resemblance. Karaage is not a flat breaded cutlet. It is bite-sized chicken, usually thigh, marinated in soy, ginger, garlic, and a little sake, then dredged in potato starch and fried so the coating goes lacy, blistered, and shatteringly light rather than forming a smooth uniform crust. Piled onto shokupan with mayonnaise and a layer of shredded cabbage, it becomes a sandwich whose logic is craggy texture and a deep soy-ginger savor, not the neat geometric cross section of a cutlet build. The pieces sit in clusters, the coating catches the mayo in its crevices, and every bite is slightly different from the last.
The craft is keeping that fragile fried coating alive against bread, mayo, and cabbage all at once. The chicken is marinated long enough to carry flavor into the meat, then coated in potato starch, which fries lighter and crisper than flour or panko and stays crunchy a little longer. It is fried so the outside is gold and crackling and the thigh stays juicy, then drained well, because any retained oil will go straight into the shokupan and turn the base greasy. The mayonnaise, often the tangy Japanese kind, is spread on the bread rather than tossed through the chicken so the coating keeps its crunch as long as possible. The cabbage is finely shredded and dry, adding cool crispness and lift against the richness. A good one holds clear contrast: airy crackling coating, juicy savory chicken, sharp creamy mayo, fresh cabbage, soft bread, all distinct in a single bite. A sloppy one collapses that contrast fast: a coating gone soft and oily, bread slicked grey underneath, chicken bland because the marinade was rushed, or so much mayo that everything reads as one wet beige texture and the soy-ginger backbone disappears.
The variations move along the marinade, the cut, and the dressing. Some lean the marinade toward heavier garlic or yuzu; some use breast for a leaner bite or stay on thigh for juiciness; chicken nanban is the close cousin where the fried chicken is dipped in sweet-sour vinegar and crowned with tartar, a wetter and tangier build with its own separate logic. Each of those treats the bird and the sauce differently enough that it deserves its own article rather than being crowded in here.