In fencing, athletes score points by hitting each other with their weapons. The goal of the sport is to use such a weapon to touch your opponent, while also using it to defend yourself from being touched.
The first part to understanding scoring in fencing, is understanding the electronic scoring system, a central piece of equipment to the sport. The electronic scoring system has revolutionized the sport, it signals to referees, fencers, and fans when a fencer is touched, while keeping score and time at the same time. For it to work, there is a complex electric system, which includes wiring inside the weapon's blade, body cords for the fencers, and a reel at the end of the piste.
The scoring system can change format, sizes, and other specs depending on which company manufactured it. However, generally it looks like a rectangular box, with a screen and lights, a green one, a red one, and two white lights. When the green light comes on, it means that the fencer on the left of the referee (the side in which the green light is placed in the machine) has hit the opponent on their valid scoring area. When the red light comes on, the same has happened, but for the athlete on the red side. We will get to the white light in a bit.
It is important to remember that fencing has three different weapons (epee, foil, and saber) with different scoring rules. Nonetheless, the electronic scoring system works for all of them, although in different settings.
The valid scoring area in saber is any part of the body above the waist, including the mask, arms, and back. To score in saber a fencer has to touch the opponent using the tip or side of their saber. When doing that, one of the colored lights (red or green) will light up, and the referee will stop the bout and award the point to the fencer whose light went on. However, in saber most of the time both lights will go on at the same time, as it is easy for fencers to touch each other at the same time. In that case, only one fencer gets a point, which is awarded by the referee based on the "right of way rules." If fencers touch each other somewhere outside the valid scoring area, nothing will happen, no lights will go on and the bout will continue.
In foil, the valid scoring area is the torso, excluding the arms. What is special about foil is that the bout is stopped when fencers touch each other off target. In that case, in foil exclusively, a white light will go on, but no one gets a point. When a fencer touches the opponent in the valid scoring area with the tip of the foil, one of the colored lights will go on, and the referee will stop the bout and award the point. As it also happens in saber, when more than one light goes on, being colored or white, the referee will award the point based on the "right of way rules."
Epee has the simplest scoring rules in fencing. The valid target area in epee is the fencer's whole body, and only touches with the tip of the weapon. If a colored light goes on a point is awarded to the fencer who touched the opponent, and if both fencers touch each other at the same time therefore both colored lights go on, both fencers get a point.
Winning in fencing depends on what stage of a competition a fencer is in. In the pool stage, the preliminary stage, wins the fencer who scores 5 points first, while in direct elimination rounds, wins the fencer who scores 15 points first. But also bouts have a set time, for bouts fencers have 3 minutes to reach five points, and in direct elimination three 3-minute periods to reach 15. If time runs out before anyone reaches the said score, wins the fencer who has the most points.
Fencing has three different weapons, foil, epee, and saber. In all three of them, the goal is to touch your opponent with your weapon, while also using it to avoid being touched by the opponent. Although that may sound quite simple, each weapon has somewhat complex rules of their own, which contribute to making fencing an exciting and fair sport.
After a bout is over and the referee has declared the winner, fencers don't just turn their backs and leave. There are rules that contribute to maintaining the sport's original etiquette and courtesy. After a bout, fencers must salute each other using their weapons and proceed to shake hands. After that, fencers usually shake hands with the opponent's coach, and the referee, although that is not a rule.
The lights in fencing are part of the electronic scoring system, which indicates a fencer touched their opponent. There are three different colors of lights: red, green, and white. The white light indicates when a fencer touched the other outside of the valid scoring area, and it is exclusive to foil. The colored lights indicate when a fencer touched the other inside the valid scoring area, and it is used in all three weapons.