Kaminari-okoshi, often called merely okoshi, is a popular Japanese confectionery, similar to rice crispy treats. The main ingredient in okoshi is expanded rice, created by roasting rice grains until they pop. A mix of sugar and butter or corn syrup is used to hold the rice together, and after the additional ingredients have been added, the mixture is formed or pressed in trays, left to dry, then cut into square shapes.

This crispy Japanese treat first appeared during the mid-Edo period in Japan and was primarily sold by street vendors in the vicinity of Buddhist temples in Asakusa, one of the districts in Tokyo. Originally, peanuts were added to enrich okoshi, but modern versions also include other nuts, dried fruit, chocolate, or sesame seeds, along with other exotic and interesting flavors such as matcha green tea or caramel.

Most okoshi is nowadays factory-produced, created in an array of unusual flavor and color combinations, and sold in decorative, colorful boxes. In the Asakusa area, there are still traditional street vendors who prepare this brittle snack and demonstrate the entire procedure.