If you are referring to the book itself, please go to The Universe of the Four Gods.
- "......Sairou's administration is constantly changing, Kounan's land is much too small and besides, the government there is too lenient in terms of its regulations. Both are too unstable for taking in such a large amount of citizens at once."
- —Temudan Rowun
The Universe of the Four Gods (四神天地) is the world where Takiko Okuda, Suzuno Osugi, Miaka Yuuki and Yui Hongo were transported. It takes the form of a handwritten manuscript written by Takiko Okuda's father, Einosuke Okuda. The first priestess is the aforementioned Okuda Takiko, Einosuke's daughter, who opened the book and became the Priestess of Genbu.
- Hokkan, a cold, snow-filled nation to the north, worships Genbu. Genbu was summoned two hundred years ago (in the book) by Takiko Okuda, a young girl from the Japan opf the Taisho era (around 1923). At the time, Genbu was considered a curse and feared by his people. Takiko was the first priestess to enter the Universe of the Four Gods and her necklace, a gift from the prophet Anlu, becomes a Shinzaho necessary for future priestesses to have in summoning their respective gods. The country seems to be patterned after the cultures from the Mongolian Empire.
- Sairou, a mountainous, desert region to the west, worships Byakko. Byakko was summoned ninety years ago by Suzuno Osugi, a girl from the Taisho/Showa era. Suzuno was the second priestess to enter the Universe of the Four Gods. A mirror she held during her summoning ceremony becomes another Shinzaho. Even though Byakko was called to service more than a century later (Universe story-wise), Suzuno was eight years old when Takiko left to summon Genbu, entered the Universe for the first time few months after Takiko's adventures (right after the Great Kanto Earthquake of 1923), and would properly return to the book and summon Byakko when she was a middle school student (probably around the very early Showa era, from 1926 onwards); this is because time in the book of the Universe of the Four Gods flows faster than the 'real world', and only calls up the Priestesses when it's exactly needed. The land of Sairou bears great resemblance to Central/Western Asian lands like the Silk Road, Tibet, the actual Xinjiang/Inner Mongolia area, etc. At the time of Suzuno's first arrival, the country is in a crisis: the recently enthroned Emperor Nahido sees his authority challenged by the local cult known as "Three Priests Alliance" and its charismatic leader, the Great Priest.
- Kutou, marred with a history of battle and invasion, lies to the east and worships Seiryuu. Seiryu was the third god to be summoned. He was brought forth by Yui Hongo. Yui enters the book at the same time as Miaka, Priestess of Suzaku. Her Shinzaho is the teardrop earring she wore during the summoning ceremony. Kutou is one of the two nations modeled after Imperial China and, in the original series, it's ruled by its unnamed Emperor with quite the iron fist. Nakago, the leader of the Seiryuu Senshi, is the Emperor's right hand and almost the de-facto ruler.
- Konan, a forested, green country to the south, worships Suzaku. Suzaku was the last of the beast gods to be summoned. He was brought forth by Miaka Yuki. Miaka's Shinzaho was believed to be a ring she wore, but later it was revealed in Fushigi Yuugi Eikoden as her and Taka's unborn child. The country is designed after Imperial China as well: when Miaka arrives to Konan, the country is being led wisely by Emperor Saihitei, better known as Hotohori.