Influences from both French and Chinese culinary traditions are believed to have contributed to its development in Vietnam, as well as to the etymology of its name.

[8][9][10][7] The Hanoi (northern) and Saigon (southern) styles of pho differ by noodle width, sweetness of broth, and choice of herbs and sauce.

[11] Phở likely evolved from similar beef noodle soups found in neighboring countries, including Thailand, and the Chinese provinces of Guangdong and Yunnan, where such dishes are common.

[12] However dishes with a similar preparation to phở using water buffalo meat, such as xáo trâu have long been staples to the rural cuisine.

[13] The modern form emerged between 1900 and 1907 in northern Vietnam,[1][8] southeast of Hanoi in Nam Định Province, then a substantial textile market.

[15][16] The Yunnan-style herbal beef soup is called niupafu (牛扒呼) or ngau paa fu in Cantonese.

[17] From the pole hung two wooden cabinets, one housing a cauldron over a wood fire, the other storing noodles, spices, cookware, and space to prepare a bowl of phở.

[20] Around 1925, a Vân Cù villager named Vạn opened the first "Nam Định style" pho stand in Hanoi.

[19] In the late 1920s, various vendors experimented with húng lìu, sesame oil, tofu, and even Lethocerus indicus extract (cà cuống).

[14] No longer confined to northern culinary traditions, variations in meat and broth appeared, and additional garnishes, such as lime, mung bean sprouts (giá đỗ), culantro (ngò gai), cinnamon basil (húng quế), Hoisin sauce (tương đen), and hot Sriracha sauce (tương ớt) became standard fare.

[25][26] Officially banned as capitalism, these vendors prized portability, carrying their wares on gánh and setting out plastic stools for customers.

The broth consisted of boiled water with MSG added for taste, as there were often shortages of various foodstuffs like meat and rice during that period.

[29] Bread or cold rice was often served as a side dish, leading to the present-day practice of dipping quẩy (deep-fried wheat flour dough) in pho.

Restaurants specializing in phở appeared in numerous Asian neighborhoods and Little Saigons, such as in Paris and in major cities in the United States, Canada, and Australia.

[citation needed] In recent decades, phở has evolved beyond its traditional form, with new variations emerging to cater to modern tastes and preferences.

"[10][19][45] Possibly the earliest English-language reference to pho was in the book Recipes of All Nations, edited by Countess Morphy in 1935: In the book, pho is described as "an Annamese soup held in high esteem ... made with beef, a veal bone, onions, a bay leaf, salt, and pepper, and a small teaspoon of nuoc-mam (fish sauce).

[24][47] Gustave Hue (1937) equates cháo phở to the French beef stew pot-au-feu (literally, "pot on the fire").

[10][21][49] Another suggestion of a separate origin is that phở in French has long been pronounced [fo] rather than [fø]: in Jean Tardieu's Lettre de Hanoï à Roger Martin Du Gard (1928), a soup vendor cries "Pho-ô!"

This etymology is supported by the 1931 dictionary definition of phở and the influence of Chinese culinary traditions, including the use of rice noodles and spices in the broth.

Originally eaten by commoners near the Red River, it consisted of stir-fried strips of water buffalo meat served in broth atop rice vermicelli.

(Chinese: 肉粉; Cantonese Yale: yuhk fán; Vietnamese: nhục phấn), with the last syllable elongated.

Seasonings can include Saigon cinnamon or other kinds of cinnamon as alternatives (may be used usually in stick form, sometimes in powder form in pho restaurant franchises overseas), star anise, roasted ginger, roasted onion, black cardamom, coriander seed, fennel seed, and clove.

The spices, often wrapped in cheesecloth or a soaking bag to prevent them from floating all over the pot, usually contain cloves, star anise, coriander seed, fennel, cinnamon, black cardamom, ginger, and onion.

Careful cooks often roast ginger and onion over an open fire for about a minute before adding them to the stock, to bring out their full flavor.

The Northern pho is often described as subtle and light on spices while having a deep savory taste from beef bones.

[67] The variations in meat, broth, and additional garnishes such as lime, bean sprouts, ngò gai (culantro), húng quế (Thai basil), and tương đen (hoisin sauce), tương ớt (chili sauce) appear to be innovations made by or introduced to the South.

[68] Other provincial variations exist where pho is served with delicacy meats other than beef or chicken, such as duck, buffalo, goat, or veal.

After the Fall of Saigon in 1975, the Philippines welcomed refugees into its territories, resulting in thousands of Vietnamese from southern Vietnam taking shelter on the Filipino island of Palawan.

[73] At Phở Bình, American soldiers dined as National Liberation Front agents planned the Tết Offensive just upstairs.

A soup of Vietnamese origin typically consisting of rice noodles, onions, herbs, seasonings, and thinly sliced beef or chicken in a clear broth."pho".