Often eaten as a snack in northern China, deep-fried rice clusters called guoba are eaten as a main dish in the rest of the country, served just-fried and with sauce poured over the top, tableside. On impact, the deep-fried rice cakes give off a crackling sound, hence its nickname, ping di yi sheng lei, or clap of thunder on a plain.
Throughout Chinese history, there have been many attempts to create dams to control the supply of water along the banks of the Yellow River, China's main inland waterway. Devastating floods or droughts along different sections were common, and many emperors made it a priority.
Legend has it that after the completion of one such project, during the Qing dynasty (1644-1911), there was a celebratory feast at a local restaurant. Officials ate and drank until the wee hours of the morning, and finished all the food.
Fearing he would be punished for not serving enough, the cook searched for something to serve. He spotted some deep-fried rice cakes intended as staff snacks. He deep-fried them again, and made a thick, red sauce on the side consisting of chilli, prawns and pork. The officials loved the ad hoc creation and asked the chef the name of the dish. Knowing that they used a lot of explosives in the river works, the chef chose the thunder metaphor.
Later, during the second Sino-Japanese war (1937-1945), the dish became known as "bombing Tokyo". As a result of the recent tensions between China and Japan over the Diaoyu, or Senkaku, islands, nationalistic types may be using this alternative title.