Both Harumaki and American-Chinese-style spring rolls are based on the Chinese dish Chūn Juǎn (春卷). In Japan, the definition of Harumaki is pretty broad, and anything that's wrapped in a spring roll wrapper and fried is considered Harumaki. That being said, the most iconic filling for Japanese spring rolls involves an assortment of vegetables and protein that are sauteed and then cooked with a savory gravy. On the other hand, Chinese-American spring rolls generally do not include gravy inside the roll, and they are usually served with sweet and sour sauce on the side.