Taika (era) followed by Hakuchi
Taika (大化) was a Japanese era name (年号, nengō) during the reign of Kōtoku. The Taika  era immediately preceded the Hakuchi era.  This period spanned the years from August 645 through February 650.History
In 645, also known as Taika  1 (大化元年), the new era name was created to mark the beginning of the reign of the emperor Kōtoku.  The previous reign ended and the new one commenced in the fourth year after the beginning of Empress Kōgyoku's reign.In Japan, this was the first nengō, derived from the Chinese system of eras (nianhao); although some scholarly doubt has been cast on the authenticity of Taika and Hakuchi as historically legitimate era names.