What is the benefit of using the opposite or “reverse” sideband when receiving CW?

When receiving CW (Morse code), a radio uses a Beat Frequency Oscillator (BFO) to create the audible tones you hear. This is typically done by setting the receiver's listening 'window' to either the Upper Sideband (USB) or Lower Sideband (LSB) relative to the actual CW carrier. When you switch your receiver to the opposite or 'reverse' sideband (often labeled CW-R), the radio flips this listening window to the other side of the carrier frequency. If the radio is properly tuned, the pitch of your desired signal remains exactly the same. The main benefit of this trick is interference reduction. If an adjacent station is causing QRM (interference) because it falls within your default sideband window, switching to the reverse sideband shifts your receiver's passband away from the interfering signal, often eliminating the QRM entirely while keeping your target station clear.