Over time, food shortages have often prompted chefs to find resourceful ways to stretch ingredients, such as kartoshka, pouding chômeur, and army base stew. Okonomiyaki is just more proof that necessity is the mother of innovation.
Okonomiyaki, which roughly translates to "grilled preference," likely existed before World War II, but it was during wartime rationing that Japan truly embraced the versatile, savory pancake. As rice was running low, some chefs realized they could use cheaper, more plentiful wheat flour for pancakes, and that any readily available ingredients—namely shredded cabbage, scallions, eggs, and, if possible, pork—could be mixed into the batter and fried up into a fast and filling meal.
Once the war ended, many had developed a taste for okonomiyaki's simplicity and customizability. Now, entire restaurants exist to serve just okonomiyaki, many of which simply sell the batter and mix-ins to patrons, who then cook it themselves on a tabletop griddle. When finished, diners top their creations with a diverse array of condiments, including a sweet-savory brown sauce (known as okonomiyaki sauce), tangy Japanese mayonnaise, dried seaweed, pickled ginger, and bonito flakes.
Although okonomiyaki-only establishments are rare outside Japan, many more traditional Japanese restaurants do serve some renditions of the meal.