The Japan Liberation Front ("JLF" for short) was prior to their destruction the largest Japanese resistance organization and is one of the most successful resistance forces in the Code Geass world. They attempted to undermine Britannian Rule over Area 11 (Japan) several times with limited success.
When the Holy Britannian Empire claimed Japan and renamed Area 11, several native Japenese rebellions arose to drive the empire out. The Liberation Front is perhaps one of the most xenophibic ones as they despise any one who is Britannian, men, women, children, civillian, soldier, nobility and royalty alike. They belive Japan belongs to the Japanese and the Japanese alone and are not above killing anyone who is Brittanian, even Brittanians with more noble beliefs then others(which there are). This is demonstarted when they hold a group of innocent Brittanians hostage inside a building and held them for ransom. If their demands were not meet, they would destroy the building and every Brittanian inside it. This act of terrorism thankfully was thwarted by the combined efforts of the Empire and Zero's Black Knights who defeated the terrorists and rescued the hostages.