Teriyaki chicken is the onigirazu filling that brings its own sauce, and that sauce is the whole problem and the whole appeal. Chicken cooked in the soy, mirin and sugar glaze that thickens to a glossy, sweet-savory lacquer is one of the most recognizable Japanese flavors there is, and pressing it into a rice-and-nori packet is mostly an exercise in keeping that glaze where it belongs instead of letting it bleed into the rice.
The build is the format's baseline. A square of nori on the diagonal, a flat bed of seasoned short-grain rice, the chicken laid across it, a second even rice layer, the corners folded in to seal, a rest seam-side down, a clean cut to show the cross-section. Thigh meat is the usual choice, cooked through, glazed, then sliced or chopped into an even layer so it spreads flat and the cut shows a continuous dark, shining band rather than a lump. The defining issue is the sauce. A thin teriyaki runs, soaks the rice grey and turns the packet soggy within minutes; a glaze reduced until it is thick and clinging stays on the chicken and reads as a sharp band against white rice. The reliable builds reduce the sauce hard, coat the meat, and often set a leaf of lettuce or a layer of shredded cabbage between rice and chicken as a moisture barrier that also adds a cool crunch against the sweet richness.
The work follows from that. Chicken glazed and then left wet is the most common failure; chicken glazed, then allowed to set briefly so the lacquer tightens before assembly, holds far better. A scatter of toasted sesame or a few rings of scallion in the band cuts the sweetness, which can otherwise dominate a packet where the rice is barely seasoned. The format's usual disciplines apply: meat spread flat and to the edges so the corners carry it, the packet sealed and rested so the nori adheres, the knife wetted and wiped so the cut shows a clean glazed stripe rather than a smear dragged through the rice.
Variations mostly adjust the glaze and what tempers it. A mayo-streaked build leans softer and richer; a chilli-spiked sauce pushes it sharp; a teriyaki and egg combination rounds it into something fuller; avocado worked in trades crunch for cream against the sweet meat. Each of those reshapes the balance enough that it deserves its own article rather than being crowded in here.