Sushi is the symbol of Japanese food worldwide. And the most iconic, most familiar, style of sushi is known as nigiri. Credit Hanaya Yohei, a 19th-century sushi chef, for its popularity. These oblong pads of vinegared rice topped with raw fish are found everywhere these days, from cutting edge restaurants in big cities to neighborhood joints in even the smallest of towns.

Sushi existed for centuries before Yohei's birth in 1799. Originally developed as a method of preserving fish in rice, nare-zushi took months to create as the fish cured in the increasingly sour-tasting rice. Using rice vinegar to spike freshly made rice sped up the process, but sushi took hours to make as it was pressed in wooden boxes.

Enter Yohei, the son of greengrocers. He moved to Edo - today's Tokyo - as a young man and took to sushi making.

"Finding press-molding a bother and squashed fish not very palatable, he conjured up the idea of quickly working rice and fish together in a few deft hand moves," wrote Kikuo Shimizu, a master sushi chef, in his book, "Edomae Sushi: Art, Tradition, Simplicity." Yohei's nigiri was a big hit with busy Edo workers who didn't have time to sit down for a meal and just wanted a nibble, Shimizu wrote.

The fresh taste of Yohei's sushi also likely was preferable to the fermented flavor they were used to, Shimizu said in an email from Japan forwarded by Noriko Yokoto, who edited his book for the publisher, Kodansha International. (Yokoto posed to him my questions about Yohei and nigiri and then translated and annotated his answers.) And, of course, there was the thrill of the new that Yohei's nigiri offered.

Yohei began selling his version of nigiri around 1824. He died in 1858 but his business endured into the 1930s, according to Theodore C. Bestor, a Harvard University professor and author of "Tsukiji: The Fish Market at the Center of the World."