Occurring in 1871, the abolition of the Han system and establishment of prefecture system (廃藩置県, Haihan-chiken; Hai abolition + han + chi settle + ken prefecture) was an act to replace the traditional han system and introduce new local government. "Han system" is also translated as "."
In an attempt to wipe out feudalism in Japan, the new Meiji government, which replaced the Tokugawa shogunate, abolished hundreads of feudal clans or Han. In their place it established a new local government scheme based on geographically-defined prefectures which is still in effect today. It brought the shogunate and domain system or bakuhan taisei to a formal end, though did not remove (end?) it completely.
In the meantime Ryukyu (now Okinawa) was also annexed to the Japanese territory. That invasion is called "Enter Ryukyu" (Okinawa-Iri)
See also: Meiji era