Nyosei (Nucheng-Kuo or ”Women Fort Country”) is an island territory entirely populated by women. It lies off the Eastern coast of Hokkan.
The island is inhabited by a small, all-female tribe known only as the Nyosei Tribe. A completely independent territory, it is relatively unknown outside of scholars for most who venture to this land hardly ever return.
Under the rule of a single matriarch, women are trained in martial arts, swordsmanship, and other styles of combat to protect their home and way of life. They appear to dress in traditional Hokkan-fashion but adorn themselves with plates of armor, spears, and swords. As a highly militarized territory, the eldest daughter of the matriarch is expected to take up the role of general to the warrior women.
Female travelers are welcomed onto the island but once they enter the palace, they are not allowed to leave and are instead expected to assimilate into the tribe. Men, however, meet a much different fate.
The population collectively has a disdain for men, as they are seen as weak, unintelligent, and are only good for one thing. This is reflected in their reproduction ritual. If a man finds himself on the island at a specific time, instead of being killed on the spot, he could be captured and imprisoned. After the guards remove both of his eyes, he is then chained to a wall and enslaved to reproduce with the inhabitants. Once he dies or is close to death, the Nyosei Tribe await his next replacement.
Protected from the raging sea by tall cliffs and high walls, the main palace is situated within the inner mountains. There is an area of shallows that are patrolled regularly by its inhabitants and its shores are marked with the corpses of men who attempted to come ashore/infiltrate the island.
Although it is situated close to Hokkan, the island seems to have been spared the country's typical frigid temperatures, as greenery can be found all over. Agriculture on the island also appears to be more than enough to sustain the small population, as the tribe is able to treat themselves to frequent feasts.
In the original Fushigi Yuugi manga, Miaka and the Suzaku Seven (without Hotohori) sail towards Hokkan. When their ship is attacked by Soi of the Seiryuu Seven, Miaka, Tamahome, and Nuriko are swept away. After locating the trio, the rest of the warriors steer their burning ship towards the closest island to dock. They land on Nyosei and come ashore. There, they find the eyeless corpse of one of the crewmen impaled with swords hanging from a tree. Chiriko's celestial mark suddenly appears and he hurriedly explains that they need to put on women's clothing or they will be in great danger. But before the others can ask any questions, his mark disappears and he forgets what he was saying. But the warriors take his word and, after dressing up, they are confronted by the tribe of females who inhabit the island. The women believe all of their disguises except Mitsukake's and drag him away to their prison.
They are brought inside Nyosei Palace for an audience with the island's ruler and Miaka explains she is the Priestess of Suzaku. The matriarch invites them all to stay and prepares a feast for the company. They learn from the princess/general of Nyosei that there is a shallow canal connecting to Hokkan that has been sealed off by the island's high walls to fend off invaders. Miaka makes note of this as they are shown to the guest quarters.
That night, Miaka and Tamahome are roomed together. Tamahome removes his disguise to sleep but he crawls into Miaka's bed and the two share a tender moment. In Tasuki and Chiriko's room, Chiriko's mark returns and he demands they leave the island as soon as possible. Meanwhile, Chichiri sneaks out of his room in search of Mitsukake and he overhears the tribe's plot to disfigure and enslave his friend. Chichiri acts fast and breaks Mitsukake out just in time to meet up with the rest of the group, but he has been discovered and the guards are approaching fast.
While running from the mob of females, Miaka finds herself alone near the walls outside the main palace. She is confronted by a beautiful traveler from the West who calls herself Hua-wan and she hides her from one of the guards.
When they are out of danger, Hua-wan reveals herself to be Soi and attempts to kill the priestess. But her lightening is stopped by Hotohori's sacred sword and repelled back at her by Miaka. Defeated, Soi retreats, and the others discover that her deflected attack has struck a shallow strip of land in the canal to Hokkan.
With the raging female army at their backs, the group quickly dives off the high walls into the water and, after passing over the strip of land, the sea closes behind them and they are forced to swim ashore. Now in Hokkan, the warriors continue their journey with Nyosei Island safely behind them.
- In commentary for the manga, Yuu Watase revealed their disappointment when the Nyosei Island sequence was cut from the anime because the production company complained an island full of women was “too risqué.”
- Although omitted from the anime adaption, a similar story is told in the OVA "Fushigi Yuugi: The Tale of the Forbidden Women's Hot Spring Resort" where the island is replaced with a female-only resort in the Kanto Region of Japan as both the Suzaku and Seiryuu warriors attempt to vacation there.
- The princess/general of the island is also shown in this short but as the hot spring’s greeter.
- While seen as filler by some, the events on the island provide manga readers with a better understanding of Chiriko’s powers that the anime did not elaborate on.
- Despite its status as an independent territory, the island still worships the Beast God Genbu who guards all lands to the North.
- When Miaka and the seven jumps into the sea, Tasuki, with his famous fear of water and inability to swim, is implied to have swam from Nyosei to Hokkan’s shore.