Issenberg, a Philadelphia writer and Swarthmore grad, is an authority on sushi, having spent 15 months researching it for his book, The Sushi Economy, due out next month.
And while he's happy to talk of sashimi in Sapporo or how to find unagi in Uruguay, his real point is that sushi transcends geography.
While those little fish-and-rice concoctions may indeed trace their roots to 19th-century Tokyo street stalls, the stuff that millions eat today is actually a modern reinvention.
Sushi as we know it began about 1970, when Japanese air shippers needed something to send back home in the cargo planes that crossed the Pacific laden with radios and other exports to the West.
They discovered Canadian fishermen were routinely throwing away North Atlantic bluefin tuna - fish that could fetch tens of thousands of dollars if brought fresh to Tokyo's massive seafood market.
At the same time, Norwegian engineers were developing leak-proof, refrigerated containers. And in Japan's booming economy, consumers were willing and able to spend more for top-grade seafood.
Just as hamburger joints proliferated in postwar America, sushi restaurants spread around Japan. Innovation abounded, such as conveyor-belt sushi bars, where diners picked food off plates as they rolled by.
As Japanese firms expanded overseas, sushi came too, taking root first on the West Coast, then spreading from Australia to Austin, Texas. Japanese sushi chefs - trained to slice fish and roll rice just so - found themselves in growing demand, and some, like Nobuyuki "Nobu" Matsuhisa, founded sushi empires.
The market begat suppliers as well, specialty distributors who could work fast and flexibly enough to move tuna from the open ocean to dining rooms half a world away in a few days.
