Taking a Peek Into Sushi's Past With Hasaki's Hako-Zushi
Sushi originated 1000 years ago in the mountainous region southeast of Tokyo as a method of preserving fish. Someone discovered that fish soaked in a rice solution generated lactic acid, which preserved the fish. The word for sushi in Japanese is similar to the word for "sour." Eventually the fish was placed on top of rice, and as the rice fermented, the fish would be pickled. Judging from similar systems still in place in various parts of the world, one suspects that the fish so preserved tasted pretty funky.
Eventually, the rice would be vinegared to mimic the fermented flavor, and the fish ritually place on top in little swatches, or wrapped in dry seaweed. But the middle step, known as hako-zushi ("box sushi") or oshi-zushi ("pressed sushi"), involved pressing fish on top of the rice into a box.
You can find hako sushi at venerable walk-down sushi restaurant Hasaki in the East Village. The substantial appetizer ($13) gives you a choice of mackerel or salmon, pressed and then deboxed, so that you get eight fingers of rectangular sushi with pickled mackerel, shiso leaves, and tightly pressed rice, with a film of sweet potato starch or some other gelatinous substance on top. It's delicious, and would be fun to try making at home. 210 East 9th Street, 212-473-3327