Jon Moxley, the wrestler formerly known as Dean Ambrose, finished up his nine-year run with WWE on April 21 by putting on the black tactical gear of The Shield. After standing next to Seth Rollins and Roman Reigns one last time, he walked away from WWE with a world of possibilities at his fingertips.

His next match, six weeks later, couldn't have been much further away, in terms of distance or the impact.

The Ryogoku Kokugikan Sumo Hall in Tokyo is more than 6,000 miles away from the TaxSlayer Center in Moline, Illinois. The man across the ring from him was a familiar face who also had voluntarily stepped out of the WWE system with full belief in himself, Juice Robinson.

The two men had started their careers in the WWE's developmental system together in Florida Championship Wrestling. Back then, it was Ambrose and CJ Parker doing local shows at small buildings all over Florida, hoping to one day realize their dreams of stardom.

Robinson was about the only thing that felt familiar to Moxley in that ring. Gone was his jeans-and-tank-top wrestling attire, cast aside in favor of simple black trunks and black wrestling shoes. The fans at Tokyo's famed Sumo Hall were an unknown. The boys in the back, for the most part, were strangers.

The most jarring difference, Moxley said, was the tangible feeling of the reins being lifted from him inside the ring. In WWE, chairman and CEO Vince McMahon has his hands on everything that goes out on the air. In this match, at New Japan Pro-Wrestling's Best of the Super Juniors final on June 5, things felt much more, well, raw.

"[In WWE,] it's almost like Vince is in the ring with you, the producer is in the ring with you," Moxley told ESPN. "It's like you have two little bubbles on your shoulder, like three heads in the ring. All of a sudden when I got in the ring [in New Japan], five minutes into the match I was like, there's no chatter. There was no producer-ref-Vince chatter. It was like silence. And I didn't expect that. I was like, 'Whoa, I'm alone again. It's just me in the ring.' And then I just started beating the [crap] out of Juice and I was like, 'Oh yeah, this is what I used to do.'"

The 33-year-old Ohio native was one of WWE's top stars, reportedly earning seven figures annually by the time he departed. But in recent years, Moxley felt creatively unfulfilled inside of the WWE. Like Robinson, Cody (Rhodes), Shawn Spears (Tye Dillinger) and Sami Callihan, among others, Moxley elected to bet on himself and explore the world of pro wrestling outside WWE. Unlike everyone else on that list, save for Cody, Moxley had made it to the highest levels of WWE as a former WWE champion and three-time Intercontinental champion.

When his contract expired on May 1, Moxley declined an extension offer (claiming to have never looked at it) and instead signed on with arguably the two biggest alternatives to WWE -- a written deal with upstart All Elite Wrestling, and a separate side contract with New Japan Pro-Wrestling (NJPW). After he attacked Chris Jericho and Kenny Omega to close out AEW's debut show, Double or Nothing, it was on to Japan.

Moxley beat Robinson that night to win the IWGP United States heavyweight title. He has had a handful of matches since, including his AEW in-ring debut in a violent match against Joey Janela on June 29, but his schedule is about to get more intense. This summer, he'll spend more than four weeks touring Japan as part of NJPW's prestigious G1 Climax tournament.

Moxley's match against Juice Robinson brought him up against another wrestler who left behind the WWE in search of something more. TV Asahi/NJPW/AXS TV

The history of the tournament goes back well over three decades. It was originally called World League when it started in 1974, then MSG League, International Wrestling Grand Prix and World Cup Tournament. Past winners of the G1's predecessors include Hulk Hogan, Andre the Giant and Antonio Inoki. Hogan won the IWGP championship, which later became NJPW's top non-tournament title, in 1983, one year before his first run as WWF champion.

This year's tournament is the 29th edition of the G1, NJPW's annual showcase that serves as the backbone for the majority of the stories and rivalries they tell in a given year. The action begins on Saturday, live on AXS TV from the American Airlines Center in Dallas. This is the first time the tournament will begin in the United States.

With the winner getting an IWGP heavyweight title shot at Wrestle Kingdom, New Japan's biggest show of the year, the tournament represents one of the clear differences between New Japan's sports-centric presentation and WWE's entertainment-focused approach. The G1 is a 20-man, round robin event that evokes the World Cup or March Madness while building out stories, night after night.

Moxley had only ever wrestled in Japan during WWE's once-a-year trips to the country. Outside of watching tapes of it as a kid, and with just two NJPW matches under his belt, Moxley is going into an intense stretch of 18 events in 10 different cities.

He said he is not worried about the physical demands of the G1 tour. Moxley suggested he has experienced perhaps worse in WWE, including a streak during which Moxley was headlining shows all over the world and going through tables at a stunning pace.

"[In WWE,] it's almost like Vince [McMahon] is in the ring with you, the producer is in the ring with you. It's like you have two little bubbles on your shoulder, like three heads in the ring. All of a sudden when I got in the ring [in New Japan Pro-Wrestling], five minutes into the match I was like, there's no chatter. There was no producer-ref-Vince chatter. It was like silence. And I didn't expect that. I was like, 'Whoa, I'm alone again. It's just me in the ring.' And then I just started beating the [crap] out of Juice and I was like, 'Oh yeah, this is what I used to do.'" Jon Moxley

"I expect it to be a grinding tour," Moxley said. "But dude, I've done the most horrific WWE European and worldwide tours that you could imagine. Like no days off, 14 days straight, 25 minutes every night in the main event. Going through tables every single night."

Putting the wear and tear on his body to the side, taking his time or playing it safe would fly in the face of how he has approached wrestling since leaving WWE.

"I could have done the G1 next year, done some more matches in Japan, got a feel for the style," Moxley said. "I've gotta do this s--- in four weeks. Basically, this is a crash course in New Japan. This might be my one opportunity do it.

"I heard a lot of stuff about how hard this tournament is, how grueling this tournament is. When one of the top companies in the world with such great history invites you to their flagship event -- yeah, it'll be hard, but you only get one life. What am I gonna say? No? Why would I be saying no?"

It'll be an opportunity for Moxley to face a lot of the biggest names NJPW has to offer in a short window. At the end of the round-robin portion of the tournament, the winners of each block face off for the G1 Climax championship and a Tokyo Dome title shot Aug. 12 at Tokyo's Nippon Budokan.

It's what Moxley was after when he left WWE -- getting away from its approach to wrestling, which can really pour it on sometimes when it comes to childish humor.

"It's kind of like March Madness or something like that," Moxley said. "Pick your favorite guy and you can follow him through the tournament. Stories will play out through the tournament. Everybody will play a different role. Somebody might bang their leg up in the first match, and then they have to deal with having a hurt leg for the rest of the tournament. Like actual pro wrestling stories."

While G1 Climax action kicks off Saturday -- on a card headlined by IWGP heavyweight champion Kazuchika Okada against longtime rival and legend Hiroshi Tanahashi -- Moxley's first match is in Tokyo on July 13.

Moxley is one of five singles champions in the field for New Japan Pro-Wrestling's G1 Climax tournament, a 20-man round-robin event that evokes comparisons to soccer's World Cup. TV Asahi/NJPW/AXS TV

So what can Moxley expect as an import wrestler stepping into Japan's brightest spotlight for the first time? Robinson, Moxley's first opponent in Japan (and final opponent of the group stage in the G1), offered some insights into the grind.

This will be Robinson's third straight G1. The key, for him, is just staying healthy. Robinson said he sprained his MCL in his second singles match two years ago, and last year, he performed throughout the tournament with a broken left hand.

A little help from his friends Moxley got some extra help from a couple of friends from the WWE locker room who have intimate knowledge of the tournament and NJPW as a whole -- former WWE and IWGP champion AJ Styles, who took part in two G1s; and 2012 G1 runner-up Karl Anderson, who participated in the G1 Climax tournament six times from 2010 to 2015 while he was in Japan. "[Anderson] was like, 'Dude, you're gonna have so much fun. You're gonna love it. It's right up your alley,'" Moxley said. "I was like, all right. That made me feel better. A.J. Styles told me the same thing. He was like, 'Oh, you're gonna have so much fun. You're gonna love it.'"

"When you're deep within it, it starts to be like, 'Oh, my God, I don't know how I can do any more of these at the peak level that they need to be had at,'" Robinson said. "It's fun, but it's definitely a tournament that when it's over, you want to go out and just drink about 12 beers and fall asleep for two days."

Will Ospreay, one of NJPW's brightest young stars, also will be making his G1 debut this summer. He hasn't experienced the grind yet himself but figures he understands what it's all about. Ospreay just won NJPW's Best of the Super Juniors tournament, which is like the G1 for lighter athletes.

Ospreay, 26, will be one of the most important wrestlers to watch over the next two months of G1 action. The last year has seen a changing of the guard in NJPW, as the landscape of wrestling as a whole has been altered; just look at the path Moxley has taken over the past few months. On the NJPW side of things, Kenny Omega, NJPW's biggest foreign star, has moved on to AEW. Even the G1 looks dramatically different this year, with six of the 20 wrestlers in this field making their debuts, including three former WWE-based talents -- Moxley, Robinson and KENTA, formerly known as Hideo Itami.

Ospreay, who moved two weeks ago to Japan full time from the United Kingdom, believes he is ready to fill that void as the company's top foreign-born star.

"I'm looking forward to being handed the ball," Ospreay said. "But the fact is, I haven't been handed anything. The idea with this is someone has left, someone needs to pick it up."

KENTA is very well-known to Japanese fans from his years as one of Pro Wrestling NOAH's top stars. The G1 will mark not only his NJPW debut, but his return to his home country. KENTA said he has a chip on his shoulder to show fans he is better than how he performed during a tumultuous, injury-riddled time in WWE.

"I came here to prove who I am," KENTA said, via a translator. "My WWE career wasn't good. But I had a great experience.

"I have been waiting for this opportunity for a long time. I want to prove who I am to the world, so this is a great opportunity to do that. It means a lot to me."

Moxley's thoughts on the G1 are pretty clear: "When one of the top companies in the world with such great history invites you to their flagship event -- yeah, it'll be hard, but you only get one life. What am I gonna say? No? Why would I be saying no?" TV Asahi/NJPW/AXS TV

In many ways, Moxley sees this moment in NJPW as the 180-degree difference from WWE he was longing for in his final days with the company.

G1 Climax field Block A Block B Kazuchika Okada Tetsuya Naito Hiroshi Tanahashi Jay White Kota Ibushi Jon Moxley Will Ospreay Tomohiro Ishii KENTA Juice Robinson Zack Sabre Jr. Hirooki Goto SANADA Toru Yano EVIL Shingo Takagi Bad Luck Fale Taichi Lance Archer Jeff Cobb

"Being over there [in Japan] was like, 'Oh, it's just pro wrestling,'" Moxley said. "It's like the pro wrestling I grew up on. Pro wrestling is a sport. It's simple. It's a story, two guys, the conflict. We're having a fight in the ring. Wins and losses. New Japan is very sport-centric. If you're kind of burned out on sports entertainment and watching people have big, long diatribes in the ring and you want to get back to sweat flying, people chopping each other, suplexing each other, going for submissions, the sport of professional wrestling -- if you miss that, then the G1 is gonna be for you."

Moxley very easily could have rested his body after eight tough years in WWE. Instead, he said he is making up for lost time and having the one big run in Japan he always had hoped he would. Moxley will put himself through the ringer, having brutal matches against the likes of bruisers Tomohiro Ishii and Shingo Takagi, then jump on a bus or bullet train and do it all again the next night.

"I expect it to be hard," Moxley said. "I expect it to be a lot of rough mornings. The thing with me is, most likely I'll have the foot on the gas pedal pretty hard the entire time. Whether that's smart or not, that's just the way I'm wired. I expect it to be fun."