Surfing is an incredibly unique sport that utilizes an equally unique scoring system. Each surfer is able to catch as many waves as they can within the time limit, though only their top two scores will count. Each wave they ride will be scored by five judges on a scale from 0.1 - 10, with 10 being a perfect wave. The best and worst score for each wave will be dropped, and the average of the other three judges will determine the official score for that wave.

How do the judges actually determine what scores they will give though? NBCOlympics.com spoke with a few experts to get a more in-depth understanding of how the scores shake out.

The judges' criteria in surfing changes drastically depending on the venue. Teahupo'o itself is a one-of-a-kind venue, so it will require the surfers to focus on very different aspects of their riding than at other events or, say, the Tokyo Games.

The main thing the judges want to see at this location is barrel rides, also known as tube rides. At Teahupo'o, the rapid transition from deep ocean to a shallow reef causes the oncoming waves to fold over themselves, creating hollow pockets, or barrels, that surfers are able to occupy ... briefly. 

Simply riding within a barrel does not guarantee an appealing score though, as multiple boxes need to be checked in order to achieve a desirable number. The scores are also scaled to the wave conditions at that specific time.

"The foundation of judging is based on comparisons with other waves on the day," said Erik Krammer, Technical Director for surfing at the Olympics. "Those are attached to the judging criteria including commitment, degree of difficulty, drop, size of wave, and critical section."

First and foremost, the surfers must commit fully to a wave to earn a high score. If they gingerly ease their way into a big swell, their score will not be favorable. This naturally transitions into degree of difficulty, which is impacted by just about every other factor in the judging process. The harder the wave, the higher the score.

This goes for both the wave shape itself and the way a surfer elects to ride it.

The biggest, gnarliest waves always hold the opportunity for the most points. Additionally, surfers need to toe the line betwee making the ride as hard as they possibly can, and wiping out. Even if they toe that line too much and do wipe out, it can still be worth it as opposed to settling for an easy ride.

The larger and more difficult the barrel, the better a rider will score.

Ways to add degree of difficulty can vary. In Teahupo'o, surfers not only want to charge onto the biggest barrels, but they want to drop in as late as they can, ideally going airborne on their way down into the wave. From there, they should look to position themselves deep in the barrel, disappearing from the sight of spectators behind the crashing wall of white water for as long as they possibly can.  

"The judges will look at the amount of travel time in the barrel even if they fall at the end, taking into account the length and difficulty of the wave," explained Krammer. 

When the mouth of the wave is just about to close, surfers hope to come flying through the spit, bursting back into sight while maintaining control on their board for a clean exit to finish their ride. For a good score, it's necessary for riders to complete their tube ride.

So, what about a perfect 10? Getting that score from the judges is a rare event — but it's special whenever it happens.

At the World Surf League event in Tahiti earlier this year, Brazil's Tatiana Weston-Webb scored a perfect 10 on one of her waves. Another Brazilian, Gabriel Medina, almost got one during Round 3 of the Olympic competition (he ended up with a 9.90).

As Luli Pereira, the Director of Officiating and Head Judge for the WSL (and also a member of the judging team for these Olympic Games), explained, those high scores often come on waves that have a "wow" factor to them.

"Normally it's a wave that kind of puts you in doubt that the surfer is going to be able to come out of the barrel," Pereira explained.

In a sport where the judging scale alters with the weather conditions and there are five judges, consistency can be a concern. As previously noted, the highest and lowest scores are not counted towards the average of a wave. That is not the only measure taken to ensure the scale remains as clear and accurate as possible. 

"At the start of the heat, the Head Judge will scale the first significant wave of the heat so that all the judges are consistent at the start," Krammer revealed. "The judges will always be watching the conditions before the start of the competition to see the potential of the conditions in that moment." 

Krammer also clarified that these expectations are not just discussed between the judging panel, but communicated to the surfers as well. 

"There is a technical meeting the day before the competition where athletes and coaches are briefed on many technical elements, including judging criteria."

The scoring system in surfing can appear difficult to grasp since it can differ so greatly from not just day-to-day, but heat-to-heat.

In Teahupo'o, though, it's pretty simple: Look out for the biggest barrels and the scariest rides.