There are few Olympic disciplines with such sheer variety as cross-country. With a mixture of sprints, relays and marathon-style events contested over a gruelling programme, the athletic demands are second to none.
The sport also requires the ability to perform two different techniques: a "classic" style – allowing only for straight propelling, with uphill slopes mounted in a herringbone walk – and the faster skate-skiing method, which involves moving the legs diagonally.
"There are a lot of different things to think about," said Alex Harvey, the Canadian sensation who showed his class last season by winning 50km gold at the 2017 World Ski Championships in Lahti, Finland.
"It's not quite like trying to get Usain Bolt to run middle-distance, though. Our sprints are over 1500m, so cross-country athletes tend to be physically similar to middle-distance runners. Our sprinting requires endurance. But it's a very broad spectrum of races. I'm going to race all six. I feel like I'm hitting the peak of my career and that I've got a legitimate chance of winning a medal in the four individual races."
The cross-country programme at PyeongChang 2018 consists of the ladies' skiathlon (10 February), men's skiathlon (11 February), men's and ladies' individual sprint classic (both 13 February), ladies' 10km freestyle (15 February), men's 15km freestyle (16 February), ladies' 4 x 5km relay (17 February), men's 4 x 10km relay (18 February), men's and ladies' team sprint freestyle (21 February), men's 50km mass start classic (24 February) and ladies' 30km mass start classic (25 February).
The skiathlon is a race in two parts: the first half is raced classic style, before racers change skis and use the "free" technique – i.e. a skate style.
"Skiathlon is actually my favourite race because I enjoy doing both styles," Harvey said. "It's the first race at PyeongChang, so that's exciting.
"With classic technique, you're essentially walking on skis. It's linear, and you glide with each stride. You have to get your wax right in the middle of the ski to get maximum propulsion.
"With skating, you're basically ice skating on snow – but you're using your upper body as well. You don't need kick wax, because the ski is on its edges, so it glides further and faster. I've been getting my best results in skating style recently, but I like both, so I'm really targeting the skiathlon."
Key skills & top tips
While technique is obviously critical if you're going to win medals, all athletes at the top level have great ability. The crucial differentiators between winning and losing, according to Harvey, are athleticism and the right skis.
"It comes down to who is strongest on the day, mainly," he said. "There's no substitute for training, and working hard. I've done years of persevering through rough patches to get here. I've trained with the same coach since I was 16, usually twice a day. And you need to do a lot of competition, too. It's the only way to improve.
"Your skis are also absolutely vital. You can blow a race because of bad equipment. You can be at your strongest but finish 30th if the skis aren't right. And it works the other way, too. Recently I finished second in a world championship race. I was very tired, but the skis were so good, they got me on the podium. You really do need a good horse to win!"
"You've got to start with Marit Bjoergen, from Norway," Harvey said. "She's the most successful skier ever in our sport, with well over 100 world cup wins. An absolute legend. She can break the record for the most gold medals in our sport in Korea – and she's a great person, too.
"The whole Norwegian team is so strong, too, especially Heidi Weng, who has been top of the leaderboard this season. The USA team could also do very well. Jessica Diggins and Sophie Caldwell have been getting some results.
"There are some great individual Swiss and German racers, too, but the big battle will be between the Swedes and the Norwegians."
"My previous two Olympic experiences have been quite different," Harvey said. "At Vancouver 2010, our team came in with low expectations and went way beyond them. We got fourth in the team sprint and some really good individual finishes, too.
"We carried our confidence over into Sochi 2014, and came in with such high expectations. But we weren't able to deliver. We got a reality check.
"Since then, we've changed a lot of things, especially on the technical side. We have two new European wax technicians, a new stone grinding machine to prepare the skis, and I even changed ski companies.
"I feel better set up on the morning of a race now. We have learned a lot and I think we come into PyeongChang with good experience. My season has been really steady and included a few podiums."
His rivals will come from the usual places: "The Norwegians, the Swedes," he said. "Dario Cologna, of Switzerland, is doing very well, and Maurice Manificat, of France, is also in form."
Only one thing is certain: if Harvey strikes gold, his trademark celebration will be on show. "I will be playing air guitar with my skis if I win!"