Cartoon showing different stages of the flare. (a) Before the flare, there is a filament (associated with the twisted field lines) under a dome-like magnetic field structure. (b) The filament starts to rise, due to the loss of the force balance. Reconnection between highly sheared or twisted field below the filament occurs, resulting in the brightening under the filament. (c) When the filament is uplifted to a certain height, an impulsive reconnection in the null point is triggered and a circular flare ribbon appeared. During this process, a current sheet forms below the filament and magnetic reconnection occurred there may enhance the brightening below the filament. (d) As the filament is uplifted even higher, white-light emission enhancement appears at the two footpoints of the filament, possibly due to reconnection between the filament and the higher background magnetic field or reconnection within the filament. The brown polygons mark locations where magnetic reconnection might occur.