What tool do referees use to ensure proper scoring in foil?

The electric scoring system is crucial for ensuring proper scoring in foil fencing. This system consists of a body cord that connects the fencer's weapon to the scoring apparatus, which accurately registers touches by detecting the electrical contact made when the weapon makes contact with an opponent's valid target area.

The advantages of using an electric scoring system include greater accuracy and consistency in determining valid hits, as it minimizes human error that can occur with manual methods. The system can also provide immediate feedback, allowing referees and spectators to see scoring in real-time, which enhances the overall experience of the bout.

In contrast, other tools like manual scoring boards and visual hand signals rely on human interpretation and can lead to discrepancies in scoring if not managed carefully. Whistles, while useful for signaling actions during a match, do not contribute to scoring accuracy. The electric scoring system, therefore, represents the most reliable method for ensuring proper scoring in foil fencing.