Slits made in firm ingredients in order to make them easier to chew. For example, very fresh squid has an elasticity as if it’s about to burst. When squeezed in the hand, the shari (vinegar rice) doesn’t stick to the squid and the sushi falls apart easily. Putting these two incompatible pieces together is one way the sushi chef’s skill is showcased. This requires a “Kakushi Boucho.” Squid meat is especially tough and if slits are not made in it, the topping will remain in your mouth long after the rice is gone.