Opening a bottle of champagne with a sword is called "sabrage." Sabrage is a technique where a bottle of champagne or sparkling wine is opened by striking the glass neck of the bottle with a saber or a specially designed champagne sword. The force of the strike, combined with the pressure inside the bottle, causes the glass to break cleanly at the neck, separating the top portion of the bottle, including the cork, from the rest of the bottle. It creates a dramatic and celebratory way to open a bottle of champagne. Sabrage is often performed at special events or celebrations.