What happened
In 645 Prince Naka no Oe (the future Emperor Tenji) and Nakatomi no Kamatari (founder of the Fujiwara house) assassinated the dominant courtier Soga no Iruka at court — the Isshi Incident — breaking Soga power.
In 646 the new government proclaimed reform edicts: land and people were to belong to the state (kochi komin), with household registers, taxation and provincial administration. “Taika” was Japan’s first era name.
Background
The reform program took Tang China as its model. Registers, taxes and provincial government all followed the template of the Chinese centralized state.
Consequences
The reforms unfolded over decades, culminating in the ritsuryo codes (the Taiho Code of 701). The result was the centralized classical state — and the beginning of the Fujiwara clan’s thousand-year career at court.