National Unification Day (Yamatai)

National Unification Day (全国統一日) is a national holiday in Yamatai celebrated annually on May 7, celebrating the foundation of the Empire of Yamatai in 865 by the first Empress of Yamatai, Empress Himiko. The day marks the start of the unified Yamataian state, which has continued in various forms to the modern day.

History
According to the historical record, the Himiko, the first Empress of Yamatai, established the Empire of Yamatai at the city of Yama-kyō, which was located at the foot of Mount Hijiriyama. Traditionally, the date was the first day of the fifth month according to the lunar calendar, though following the Aozora Revolution, the date was calculated to have been the 7th of May, 865 CE. This marked the start of the unified Yamataian state, which is officially considered by the modern Yamataian government to have been unbroken to the modern day, despite several regime changes.

The first National Unification Day was celebrated on May 7, 1865, the 1000th anniversary of the founding of the Yamataian Empire. Since then, the date has been marked by a national holiday and involves nationwide celebrations, as well as elaborate parades and ceremonies held in major cities.