Most countries date their founding on the arrival of foreign invaders -- Not Tsukishima. For thousands upon thousands of years, the Tsukihito have met every invading force with the same swords that they pass down through generations. The island nation has had their ruling family, the Bakuhatsu family, for as long as they have recorded their history through paintings and the written word -- which they had developed sooner than other cultures -- and most likely longer than even that. In the same vein, Tsukishima has only ever had two religions, which have both simply been called The Sacred Path and The Holy Path for as long as anyone remembers. The Sacred Path is originally from Seung Yua, and follows the teachings of The Enlightened One, whereas The Holy Path is a polytheistic animist religion native to Tsukishima, centered around gods known as The Kami in lieu of one enlightened mortal.
Tsukishima is effectively owned by the oldest male of Clan Bakuhatsu, more frequently called "The Emperor" than by his birth name, which becomes nearly obsolete after his coronation. Below the emperor are the four shogun, each controlling a quarter of the continent as kings, whose word is second only to the emperor's. The shogunate clans and their branches are known as "high samurai", distinguished from peasantry, merchants, lords, and daimyō by being permitted by the emperor to own and ride horses, as well as each of their male members being permitted to become samurai. Below the shogun are the 64 daimyō. It is said of the daimyō that few rule ports, some rule mines, most rule rice paddies, and all rule the small folk. The richest and most well-connected to the shogunate are typically in the east or west, whereas the less impressive daimyō live in the south -- known as the rice paddy kingdom -- and the frozen north, which was only annexed by the empire three hundred years ago. Daimyō are permitted to raise their eldest sons to be samurai and essentially act as mayors, lords, and petty kings of the continent. Below the daimyō are the landed samurai -- retired samurai who have purchased lands and have started a branch house of their clan -- and the samurai, Tsukishima's most ancient and honored caste. Below the samurai are the merchants, artisans, and peasantry, and below them, the burakumin; butchers, gravediggers, and tanners, who are considered untouchable.
Tsukishima has two neighboring countries -- Goristan and Seung Yua. Goristan is the larger of the two, spanning further than Tsukishima's fleet has sailed and taking up all of the west, as far north and south as the west seems to go. Goristan has a generally cold relationship with Tsukishima -- they have no trade or immigration with Tsukishima, having a mountainous coast, though there are very rare immigrants who are mostly fleeing persecution for various crimes. They are called Goristani, and have a more Eurasian look than Tsukihito, with round eyes and hair ranging from black to dark brown that grows on their face as thick as on their head. The Goristani have tried to invade Tsukishima three times, being repelled by Tsukishima's combined forces the first two times and washed away by typhoons the third. They possess steam power, rudimentary electricity, and gunpowder, though very little is known about these three wonders in Tsukishima until very recently. The Goristani fight with slightly-European looking Jiangs and muskets, and are thought to be loud, rude, and greedy. They cultivate cows for beef, milk, and cheese, leading to the word for Goristani in Tsukihito translating literally to "cow mouth people". It is the setting's equivalent to China and Eurasia.
Seung Yua is a small island nation near Tsukishima's southeastern archipelago, known as the Tokukokko Islands. It is largely comprised of its own ethnic group, the Seungyo, though its western coast has a thriving population of immigrants from Tsukishima and the Tokukokko islands. It is a poor country, and its people are generally seen as dirty, smelly, unintelligent, and clearly inferior to Tsukishima. Though it carries a great number of negative stereotypes, it is also seen as mystical, exotic, and spiritual, due to it being the birthplace of The Sacred Path and its predecessor, the Divine Path -- Buddhism and Hinduism, respectively -- It is believed that the founder of The Sacred Path was born in Seung Yua and came by way of raft as an infant. The Seungyo fight with curved swords, chakram, and a multitude of bizarre and foreign weapons. It is the setting's equivalent to India, Indonesia, Cambodia, and Vietnam.