The common belief points of when J-pop first came to be is when the term Ryūkōka was coined. This was occurring around the Taisho period which was just after the imperial oppressing Meiji era. This was the time when Japan began to receive outside influences from places like America. Introduced to Western genres of music such as "jazz and big band music" as well as taking inspiration from their newly obtained freedom from the Meiji era, they began to create music to reflect their newly freed feelings. Using Western music techniques, gained a lot of popularity. (J-Pop Wikipedia)

During the beginning of the 1960s was the birth of a more modern style of music with influences from popular American artists such as Elvis which led to the birth of the genre called rockabilly and would be the start of rock within Japan. (Rokabiri) Later on, this rock genre would take influences such as visual kei fashion. Around the 1970s, electronic music began to see a rise in popularity and artists began to experiment with fusing electronic music with pop to give birth to a new genre called electropop/technopop. ( A brief guide to techno-kayō)

One of the most popular genres of J-Pop even to this day is city pop. It is characterized by its upbeat and catchy melodies, lush arrangements, influenced from kayoukyoku, and a fusion of various musical styles, including pop, funk, disco, and jazz. The term referred to the urban lifestyle and cosmopolitan atmosphere of Japanese cities during the economic boom during the 1980s. The music sets the mood for a sense of nostalgia in that era with themes of romance and city life excitement. (“The Endless Life Cycle of Japanese City Pop.”)

Idol anime known as Love Live, performing a concert with the voice actors representing the characters along with VOCALOID Hatsune Miku in the background