J-core is the style of hardcore techno associated with Japanese groups and DJs from the 1990s onward. It is marked by its usage of samples derived from video games and anime, colorful kawaii imagery and album graphics, and the general borrowing of elements from denpa and otaku culture. J-core music is often found in rhythm games, and forms a substantial part of the doujin music scene.

DJ Sharpnel is considered to have pioneered the style in the late 1990s, and in the early 2000s it spread through Japanese peer-to-peer networks. As anime became popular in the United States and Europe, J-core would also find appreciation among anime fans there, allowing for the development of a Western, J-core-inspired remix culture, as well as for J-core's contribution to the nightcore phenomenon of the early 2010s.