An interesting component of Japanese education is the thriving industry of juku and yobiko, after school "cram schools," which approximately 60% of Japanese high school students attend for supplemental lessons. Juku may offer lessons in non-academic subjects such as art, swimming, abacus, and calligraphy, especially for elementary school students, as well as the academic subjects that are integral to preparation for entrance examinations at all levels. Juku for high school students must compete for enrollment with yobiko, which exist solely to prepare students for university entrance examinations. Some "cram schools" specialize in preparing students for the examination of a particular school. Although it would seem natural for students to dread the rigor of additional lessons that extend their school day well into the late evening hours and require additional homework, many students enjoy juku and yobiko, where teachers often are more animated and more interesting than some of the teachers in their regular schools. Also, in many cases, the lessons studied in "cram schools" provide an intellectual challenge for students bored with the standardized curriculum of their regular schools.

Juku and yobiko are primarily private, for-profit schools that attract students from a wide geographical area. They often are located near train stations, enabling students to transport themselves easily to juku directly from school. Juku and yobiko thrive in Japan, where it is believed that all people possess the same innate intellectual capacity, and it is only the effort of individuals, or lack thereof, that determines their achievement above or below their fellows. In Japanese schools, there is the tendency to pass students with their grade cohort. Therefore, without the supplemental juku lessons, some students could fall well behind their classmates. Yobiko also exist to serve ronin, "masterless samurai," students who have failed an entrance examination, but who want to try again. It is possible for students to spend a year or two as ronin after graduating from high school, studying at yobiko until they can pass a university entrance examination or until they give up. "Cram school" tuition is expensive, but most parents are eager to pay in order to ensure acceptance into a selective junior high school, high school, or university, and thus, a good future for their children.