The popularity of sushi in Japan may have been associated with Buddhism.
Buddhism was imported in the 6th century AD, and quickly became one of the major religions. One of the rules of Buddhism was to restrain from eating meat, and fish was not counted as such.
Sesame halva is popular in the Balkans, Far East, and the Mediterranean.
Its key ingredient is tahini (sesame paste), sweetened with glucose, sugar, or honey, with various additions–pistachios, chocolate, cocoa, and vanilla or orange scent.