With a diameter of 11620.2 km, Yamato has a gravitational index of 0.98 g. It has a semimajor axis of 0.9 AU from its parent star, a Type G7 V star. Its year length is 338.8 days with a local day length of 16 hours and 2 minutes.
It has nine moons, two of which are temperate S-Class worlds. It is twice as old as Earth at 9.8 billion years old.
Yamato has an atmospheric pressure of 0.8 ATM and a mean temperature of 0.5 °C. The greenhouse gases in the atmosphere are what keep the mean temperature just above the freezing point.
Due to the planet's slightly faster rotation and the harsher axial tilt of 123°06', the world has a wilder stormier climate, most of which are large blizzards that drop copious amounts of snowfall every year.
Discovered in 5123 by the Confederate Survey Ship Oda Nobunaga, the world was quickly deemed perfect for colonization by the Planetary Colonization Bureau. The discoverer being a Japanese run ship, the people of Japan were the first to lay claim to the world.
The first settlement was on a set of islands in the north and the first town was named Kyoto. There more Japanese immigrants arrived and settled the surrounding area, slowly spreading across the entire globe.
The world required some minor terraforming, such as increasing the atmosphere. There were discussions of altering the planet's axial tilt, but studies showed that this would cause mass extinctions of many native wildlife who relied on the constant darkness and the constant light of the summer and winter months. The colonists were eager to attempt to adapt to their own natural environment and even wanted to try and engineer terrestrial life to adapt to the planet's biology.
As the centuries passed, the population increased, creating a culture that was one of the main exports of entertainment and technology for thousands of years. Despite being so far out from the center of interstellar civilization, Yamato became one of the major planets in the Confederacy. They created a resort on another world in their system, a beach resort world that was named Okinawa.
Currently there are approximately 12.2 billion inhabitants, almost all of Japanese ancestry.
The planetary government is an Imperial Democracy, where there is an emperor elected every time an old emperor dies. Every law is generated by the imperial senate, which goes over every bit of the proposed law, which is a bill at that point in time. After it is finalized, the population of every province votes on the law. If it passes there, the Emperor will either approve or deny it. If the Emperor approves it, the law becomes official.
Yamato is a country of opposites. Many cities are paragons of advanced technology, while there are many who still live off the land, using primitive (if any) technology. They cling to their Japanese heritage, many practicing Shinto while others practice Buddhism. Temples and shrines litter the planet, and many new gods have appeared in the Shinto mythos.
Due to the harsh conditions on the surface, most life is layered by multiple hard skins. At the north and south poles there live large creatures the size of trees that depend on the long unending days of summer and unending nights of winter to survive. They resemble terrestrial trees, but are mobile. During the summer, they rarely move, basking in the sunlight and absorbing its UV rays. During the winter months, they are more mobile, keeping warm by a mixture of constant movement (save for when they sleep), consuming other life forms for food and a unique form of purple bio-luminescence that releases the stored light from their sun.
The terrestrial life imported has adapted reasonably well to the conditions on the planet.