Siyi

Sze Yup
Sze Yup location in Guangdong
Chinese	四邑
Literal meaning	four counties
Transcriptions Standard Mandarin Hanyu Pinyin Sìyì Wade–Giles Ssu4-i4 IPA [sɹ̩̂î] Yue: Cantonese Yale Romanization Sei3 yap1

The Sze Yup or Four Counties, also known as Siyi in Standard Mandarin or Sz Yip in Toishanese, refers to the four former counties of Xinhui (Sunwui), Taishan (Toisan), Kaiping (Hoiping) and Enping (Yanping) in the Pearl River Delta of southern Guangdong province, China.

Xinhui is a city district and the other three are county-level cities, all four belong to Jiangmen prefecture administered from the city of Jiangmen. Since Heshan became governed by Jiangmen in 1983, Wuyi (Chinese: ; pinyin: Wǔyì; literally: "five counties", sometimes "Ng Yap"), which refers to all the five counties of Xinhui, Taishan, Kaiping, Enping and Heshan, has become an official title, and is widely accepted by the local residents today. However, among overseas Chinese, the name Siyi is still popular and frequently used.

It is said that over 100 famous people come from the Siyi or Wuyi region of Guangdong province, making the region famous for producing more entertainment stars than any other region in mainland China. As a result, the local government in Jiangmen which administers the Siyi or Wuyi cities of Taishan, Kaiping, Enping, Xinhui, and Heshan, decided to build a Stars Park called Jiangmen Star Park (江门星光园).

The area gave rise to the Siyi dialects, the most prominent of which is Taishanese (Toisanese/Hoisanese). Although Siyi and Cantonese both belong to the Yue branch of Chinese, Cantonese speakers cannot easily understand Siyi dialect.