1. Why Mooncakes Are Round Like the Full Moon
A mooncake is a Chinese sweet made by wrapping fillings like bean paste in a wheat flour skin, then baking it into a round, flat shape. During the Mid-Autumn Festival on the 15th day of the 8th month of the lunar calendar, people made them to represent the fullness of the full moon. They offered them to the moon alongside round fruits or exchanged them with close friends [1]. The Mid-Autumn Festival is also called the "August Festival" or the "Reunion Festival." "Reunion" refers to family members coming together. It is explained as an essential sweet in Chinese households because the shape of the full moon wishes for a great family reunion [1]. Placing the wish for "family togetherness" onto the round shape is an easy story to understand. However, did this meaning exist from the very beginning when mooncakes were created?
It is important to note that the mooncake as a sweet, the Mid-Autumn customs, and the meaning of "reunion" did not necessarily appear at the same time.
2. Mooncakes in the Southern Song Dynasty: Not Necessarily for Mid-Autumn
The name "mooncake" appears in books from the Southern Song dynasty (12th–13th centuries), such as Zhou Mi’s *Wulin Jiushi* and Wu Zimu’s *Mengliang Lu* [2]. The idea that mooncakes are a type of dim sum passed down from the Southern Song is based on these records [6]. However, it is explained that the mooncakes written about there were not necessarily foods for the Mid-Autumn Festival. Moreover, the Mid-Autumn customs recorded by people of the Southern Song do not mention eating mooncakes [2]. The poem by Su Shi, "Small cakes are like biting the moon, with crisp pastry and sugar inside," is often cited as an example of mooncakes. Yet, some researchers view this poem as a later forgery, and point out that "small cakes" are not necessarily mooncakes. It seems necessary to check famous stories carefully.
3. Ming Dynasty Records Link Mooncakes to Reunion
The custom of exchanging mooncakes during Mid-Autumn is said to have started in the Ming dynasty. Shen Bang’s *Wanshu Zaji* from the Ming dynasty states, "In the 8th month, people give mooncakes." Tian Rucheng’s *Xihu Youlan Zhiyu* records, "Among the common people, mooncakes are exchanged, taking on the meaning of reunion" [2]. In the Ming records mentioned in this article, mooncakes, Mid-Autumn, and reunion are linked in a single context. This meaning does not appear in Southern Song books. The round shape may have become a tool to tell the recipient, "I chose this moon-like sweet thinking of you." However, this part is only speculation. The records only show that they exchanged mooncakes and took on the meaning of reunion.
4. The Story of Secret Messages Hidden in Mooncakes
The famous story goes like this: People suffering under Yuan rule hid papers with the date of the uprising inside Mid-Autumn mooncakes and distributed them. Zhu Yuanzhang then overthrew the Yuan and founded the Ming dynasty. However, there is an explanation pointing out that this story was created by secret societies and revolutionaries in the late Qing dynasty to overthrow the Qing, and is not historical fact [2]. Chinese news articles also summarize that no historical evidence supporting this story has been found [3]. Mooncakes may have become a symbol of people coming together. There is an explanation that this story was created in a later era.
Articles from China News Service also state that no historical backing has been found for this legend [3].
5. How Mooncake Fillings Differ by Region
While the round shape is common, the fillings differ by region. It is reported that in Hong Kong and Macau, mooncakes contain lotus seed paste and salted egg yolks, while in northwestern China, some are packed with nuts [6]. The round shape carries a wish for family reunion, while the fillings reflect local life. By the way, how did this sweet come to Japan?
6. Mooncakes in Japan's Chinatowns: Yokohama, Nagasaki, and Kobe
People of Chinese descent living in Japan brought mooncakes to the country. According to research from Nagasaki University, the first place in Japan to hold Mid-Autumn Festival as a local event was Kobe’s Nankinmachi (Chinatown), but the history of selling mooncakes began earlier in Yokohama and Nagasaki [4]. It is said that the craftsman who first sold handmade mooncakes in Nankinmachi had connections with Yokohama Chinatown. At the Rose Hotel Yokohama in Yokohama Chinatown, a giant mooncake with a diameter of about 1 meter and a weight of about 60 kg (about 300 servings) is displayed. Since the 29th event is noted for 2022, it started in 1994. The start year is calculated backward from the number of events [5]. The Mid-Autumn Festival corresponds to Japan’s *Tsukimi* (Moon Viewing) and is also called the Reunion Festival. It is introduced as a day when married daughters return to their parents' homes. The round mooncake may remind people in Japan of a day for family.
7. How to Investigate Why Round Sweets Are Round
If you want to explore this topic yourself, you can start at home. Choose one round sweet you have at home and talk with your family about why it is round. Answers may include the shape after baking or good luck meanings. The meaning of the mooncake’s roundness is just one of these answers. If you have the chance to visit Chinatowns in Yokohama, Kobe, or Nagasaki, look for shops selling mooncakes and compare the descriptions of their fillings. You can verify the differences by region with your own eyes. For official information, libraries have books on Chinese annual events, and university research reports contain explanations of mooncakes and the Mid-Autumn Festival.