The definition and history of Japanese cram schools

Definition:

Cram schools are specialized schools that train their students to meet particular goals, most commonly to pass the entrance examinations of high schools or univeristies.

The English name is derived from the slang term "cramming", meaning to study hard or to study a large amount of material in a short period of time.

The history:

First of all, Japaanese cram schools started  at Heian era. People who could go cram schools were very rich until 16C.  At Edo era, cram schools spread to the public as "Terakoya". People learned reading, writing, and "Soroban" that used to culculate. And from 1960s,cram schools have more developed because many rich parents wanted better  education for their children. 1960s was Rapid economic growth.
Now, students have so many examination that they usually go to cram schools.