Original: In historical practice, the first day of a nengÅ starts whenever the emperor chooses; and the first year continues until the next lunar new year, which is understood to be the start of the nengÅ's second year.
Simplified: The first day of the first year of a nengÅ started whenever the emperor decided. This first year continued until the next lunar new year, which is understood to be the start of the nengÅ's second year.