It's hard to believe Luke Skywalker is 64 years old.

But as actor Mark Hamill recently stood on a stage at the Palace Theater in downtown Los Angeles, dressed in black, he still looked comfortable holding a lightsaber.

Thirty-eight years ago, in a galaxy that feels even more far, far away, Hamill played the iconic character in "Star Wars: A New Hope." It was a world we had never seen before. It proved irresistible for some by the epic lightsaber duels that would help define the franchise.

Now, he is set to return in the seventh movie in the series, "Star Wars: The Force Awakens," which opens in theaters Friday and is being released by The Walt Disney Company. SC Featured takes an in-depth look at the sport that helps define those duels: kendo.

Mark Hamill's role in "Star Wars: The Force Awakens" has been kept under wraps and the subject of much prerelease debate. ESPN

The Japanese martial art, whose history extends back to 17th century samurai swordplay, is highlighted in a new ESPN documentary, "Star Wars: Evolution of the Lightsaber Duel," hosted by Hamill.

"Having lived in Japan the last two years of high school, I became aware of the Japanese culture at a young age," Hamill told ESPN while filming the documentary in L.A. "I really feel that kendo has informed so much of what we have done in the films, that it is about time that it gets the recognition. That is really long overdue."

The documentary, which premieres Tuesday (ESPN, 7 p.m. ET), features behind-the-scenes training and interviews with director J.J. Abrams, actor John Boyega and the man who trained him for his cutting-edge duels, Paul Vincent.

In a series of interviews with ESPN, Hamill and the trio weigh in on the lightsaber lore.

The Star: Balancing mind and body

British actor John Boyega plays Finn, the central characer in "Star Wars: The Force Awakens." Photo by Jordan Strauss/Invision/AP

The sport of kendo focuses on mastering the fine balance between body and soul. It is a nuanced discipline, a series of patterns: strikes and thrusts, attacks and counter-attacks. There are more than 1.5 million registered dan-graded kendoka in Japan alone. There are eight levels in the discipline, the last of which can only be attempted after age 46, something that underlines the wisdom it requires.

This past May, Japan won its 15th team title in the 16th Annual World Kendo Championship in Tokyo. The participants' bamboo swords, or shinai, closely resemble the lightsaber -- without the buzz.

Like Hamill, John Boyega enters the saga as a relative unknown. The 23-year-old British actor is Stormtrooper FN-2187, or Finn, in the new film; and while he was a fan of the movie series, he had to learn the concepts of kendo to be able to accurately wield a lightsaber.

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The training, Boyega said, taught him that being aggressive wasn't always the best course of action.

"Almost being a bit too passionate, a bit too hard training, or the lack of emotional control can lead to the dark side of The Force," he said. "That would unleash a different style that was against the Jedi tradition, or the Jedi lore. I see the similarities there [with kendo], the control. It's all about peace; it's never about fighting to fight. It's fight to protect ... a reaction."

Training with kendo was also about stance and mentality.

"It was interesting how much the mentality has something to do with combat and has something to do with fighting," Boyega said. "It was all about rhythm and all about defense and all about honor. ... I think the one single perfect strike is aided by accuracy. You have time to defend and to block, and pinpoint where a strike matters the most.

"And you can end the fight in two minutes, rather than fight with all your strength and with all your anger and your emotion. ... You can pace yourself, defend and make that final blow that ends it all. ... It's a spiritual thing, a connection that sometimes, within training, if you had two kendo fighters, [the trainer] would say it's like a dance."

When asked to describe his favorite sword fight, Boyega goes old school.

"My favorite lightsaber duel will be Obi-Wan Kenobi versus Vader," he said. "And the reason being is, it was simple, laid back and you really got to see an old Jedi get to business with fighting. And he just let Darth Vader release him back into The Force. That was beautiful."

Two hands, please

Courtesy of LucasFilm

Hamill, whose role in "The Force Awakens" is a source of rampant speculation, said he was drawn to the lightsaber duels because they had the elegance of a prior era, borrowing from martial arts, knights of the roundtable and swashbuckling pirates to create something fresh and new.

When he returned to director and "Star Wars" creator George Lucas' set to film "The Empire Strikes Back," he learned more than lines. The off-set training was amped up -- weightlifting, judo and, yes, kendo classes.

"More than becoming an expert in kendo, it was more the idea of molding the body and the mind as well," Hamill said. "It's rigid in the way they train you, it's very formal and traditional-minded. It's choreographed like a dance. Every move, there is really no room for improvisation."

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So, what happened when he decided to ad-lib one of the lightsaber scenes in the movie, going with some one-handed moves instead of the two-handed combat that exclusively marked the original film?

Hamill recalled: "We choreographed a large portion of this sword fight in 'Empire' only to have George come in, look at it and say, 'I don't like it when you take your hands away. You have to have both hands on the lightsaber at all times.'

"I said, 'What are you talking about?'

"He said, 'Well it's heavy, it's like 50 pounds or something.'

"So we had to go back and take it out. You have so much more flexibility when you can spin around and switch hands and whatever."

Which is why watching the prequels made him crazy.

"These guys are doing everything but twirling them like batons!" Hamill said. "They're taking their hands off, and in their desire to make a more elaborate presentation, [George] threw that rule right out the window. I think it was really smart for George to rescind that rule. I know how hard it is, so I watched it through much different eyes and [thought], 'My God, I wonder how long it took them to do that?'"

The Director: Return to roots

Courtesy of LucasFilm

Director J.J. Abrams was 11 years old when the "Star Wars" series captured him.

"The lightsaber battles for me as a kid were always sort of the most exciting," Abrams told ESPN earlier this month in Los Angeles. "The thing that was the most powerful -- and they may not have been as choreographed -- were the lightsaber fights from the original trilogy, which some can argue were far less exciting because they weren't as dynamic. But, for me, they were incredibly emotional and very powerful.

"In 'The Force Awakens,' we tried to approach it as a rougher, more primitive kind of fight as opposed to a more choreographed one."

If anyone would be eager to embrace computer-generated imagery (CGI), you'd think it would be Abrams. He was part of innovative groups that experimented with the technology of computer animation in the making of "Shrek," co-created the TV series "Lost" and brought new energy to the "Star Trek" and "Mission Impossible" franchises before signing on as director of "The Force Awakens." But, in a back-to-the-future kind of way, the fighting in "The Force Awakens" will rely far less on CGI.

"In the original trilogy, they weren't quite as gymnastic and acrobatic," Abrams said. "Part of the reason for that, in the prequels it was sort of a different time and because of that, the sort of level of skill was sort of appropriately different. Also, the people who were actually fighting the lightsaber battles, whether it was Yoda or General Grievous, weren't just necessarily humans, so the experiences were very different."

Abrams also said one of this film's critical elements is hope, paying homage to the myriad of diverse influences "Star Wars" creator George Lucas drew from.

"Among them were Westerns and fairy tales and Joseph Campbell and Arthurian legend and, of course, the stories of samurai," Abrams said. "And when you look at those stories and certainly the Akira Kurosawa film, "Seven Samurai" [1954], it's a great example of wonderful characters and great action."

And the pulse of that action is the sword fights that captivated Abrams as a child.

"This idea of the lightsaber, this idea of this blade, this sort of myth that comes with the blade -- how they're made and what they represent and how they're used -- it wasn't just a weapon, it represented the person who had made it," Abrams said. "There's a great power to the story behind them."

The Trainer: A Jedi has to have rhythm

Courtesy of LucasFilm

Paul Vincent, a California-based trainer to the stars, as well as professional and Olympic athletes, was hired Boyega prepare for the lightsaber scenes in "The Force Awakens." His own experience and research over the years led him to the sport of kendo.

Vincent huddled with the stunt coordinator to learn the choreography, then designed drills to support the specific range of motion and strength necessary for Boyega to achieve it. During shoots, they would wake up early and train for an hour or two before four-to-six hours of stunt preparation, followed by a day on set. Sometimes, they would train afterward.

"It's not like someone just picks up a lightsaber and wheels it around," Vincent told ESPN. "What stood out for me was the precision of it. Everything has been thought about, the whole posture, the foot moves, the speed at which you move your feet. So it's very, very, very specific, the posture, the specific strikes and even the specific yells and commands to go with it."

Vincent was on the set during duels for moral support. He came away impressed.

"They were actually fighting ... it looked real," Vincent said. "It wasn't like, 'Oh, we're going to do this in post, we're going to fix this after the film.' ... I remember just being blown away by how real it already looked. There is a visceral feeling throughout the film that it's sort of really happening, it's really going on, they were really doing this work."

ESPN's Ben Houser (coordinating producer), Martin Khodabakhshian (feature producer), Craig Lazarus (VP of SportsCenter & News storytelling units) and Stacey Pressman (senior writer) contributed to this story.