JIRI PROCHAZKA PUT his arms at his side and curled his lanky, 6-foot-4 frame into a bow. In front of him was a Shinto priest, wearing a white robe and traditional black cap, called a tate-eboshi.

It was October 2019, just days after Prochazka had knocked out Fabio Maldonado on a Rizin Fighting Federation mixed martial arts card in Osaka, Japan. Following the fight, Prochazka and his coaches took a train north to Kyoto to visit Sanjusangendo, the site of one of renowned Japanese swordsman and philosopher Miyamoto Musashi’s most famous duels.

There, in front of a shrine, the Shinto priest offered Prochazka, a follower of Musashi’s principles, a blessing. He spoke only in Japanese. Prochazka’s coach, Jaroslav Hovezak, called the moving ceremony another landmark on Prochazka’s warrior path.

“It strengthened him on his way,” Hovezak said. “It was a strong experience for our team.”

Eight years ago, Hovezak gave Prochazka a copy of Musashi’s “The Book of the Five Rings,” a text about martial arts and a guide for life. Since then, Prochazka has followed Musashi’s ideals almost religiously. His evolution has taken him from a self-professed “very wild guy” who engaged in over 100 street fights, was in a soccer hooligan club back home in the Czech Republic and once chugged vodka out of a motorcycle fuel line, to someone who patterns his life after Bushido, a Japanese moral code dating back to the samurais. And that discipline has led him to the cusp of UFC glory.

“I think Jiri was more Japanese than many of us over here in Japan,” Rizin matchmaker Shingo Kashiwagi said.

Prochazka’s goal is “mastery in every part of life,” and his next step to achieve that in martial arts comes Saturday when he challenges Glover Teixeira for the UFC light heavyweight title in the main event of UFC 275 in Singapore (10 p.m. ET on ESPN+ PPV).

While a sought-after goal, the UFC championship is not the end point for Prochazka, who carries his worn, dog-eared copy of “The Book of the Five Rings” with him everywhere he goes — even the locker room. Prochazka (28-3-1), one of the most exciting fighters in the world with 10 straight KO/TKO finishes, considers earning the gold belt just another part of his “way of [the] warrior.”

“For me, it’s more important to win the fight and how to win the fight,” the 29-year-old former Rizin champion said. “How I will show my skills, my [evolution] from my last fight to this fight, that, to me, is the most important. All this fighting is about evolving. Everything for me, in this life, is about evolution. To be better, to understand better, to express better.”

PROCHAZKA’S POSTFIGHT CELEBRATIONS used to be legendary, according to the fighter’s close friend and business partner, Michal Sauer. In the early days of his career, Prochazka would throw wild parties following his bouts, complete with loud music, dancing and heavy drinking. Prochazka was at the center of the jubilation.

“He was wild at those parties,” Sauer said. “Not only dancing, but everyone was watching him. He’s a little bit like Conor McGregor. Everybody knows that he’s in the room. He was very noisy. He likes attention. Not only parties, but he liked attention everywhere he went. He was a very funny guy and everybody liked it, because he made some fun.”

At one of those parties, Prochazka, then in his early 20s, drank champagne from a used vacuum hose. At another, he guzzled vodka out of the fuel line of a friend’s motorcycle, which had its engine on.

“I think he was told he’s immortal,” Sauer said with a laugh. “Maybe he still thinks that.”

When he was younger, Prochazka attacked life much in the way he attacks MMA opponents now: recklessly, with little concern for his safety and well-being. Prochazka said as a teen he sought out street fights almost weekly, getting into more than 100 of them in his life. When that wasn’t enough, he joined a hooligan club tied to Prochazka’s local soccer team, FC Zbrojovak Brno. The club would organize group street fights with clubs that followed other teams.

Prochazka said although he once participated in 30-on-30 brawls with the hooligan group, he regrets taking part in those scraps now. As a child, Prochazka grew up with unbridled energy — a nightmare for his parents and teachers — and constantly looked for an outlet. While fighting in the streets as a teen, he fell in love with becoming the best fighter and coming up with techniques to win through trial and error. Being a hooligan was just a slightly more regulated iteration of that.

“That was the next step in this fighting lifestyle,” Prochazka said. “I was just about looking for myself, all the time. All the time. The man, we are still looking for ourselves. That’s all.”

When he was 17 years old, Prochazka started training in Muay Thai, with a bit of karate and judo mixed in. It was the structure he needed. He didn’t have to fight in the street anymore to improve his skills to be the best. This was a chance to train and compete in an even more controlled setting.

Prochazka eventually got into MMA and made his pro debut in 2012. He was far more disciplined than before, but there was still something missing. Not long after Prochazka lost to Abdul-Kerim Edilov in 2013, Hovezak brought his fighter a copy of “The Book of the Five Rings.” Hovezak was a coach on his Jetsaam team, which is led by Martin Karaivanov.

Hovezak said a martial arts coach gave him the book at age 15, and he thought it could unlock a door for Prochazka in the way it had for him. The book is popular among business people in Japan because its philosophies on winning can be applied to business and life, even though Musashi was writing about fighting — not unlike “The Art of War” by Sun Tzu.

“There is a lot of truth in the book and there is a clear order,” Hovezak said. “It can be used for both fighting and everyday life.”

After reading the book and digesting Musashi’s words, Prochazka said he began to alter his life almost immediately. Once a self-professed “very, very, very wild guy,” Prochazka started to adopt Musashi’s Bushido principles. The text, written in the 1640s, contains five books — Earth, Water, Fire, Wind and Void — and Musashi writes about ideas on martial arts, leadership, life principles and mindset.

Prochazka said he does not follow an organized religion. Instead, he has adopted “The Book of the Five Rings” as his Bible, Torah or Koran.

“For me, it’s something like that,” Prochazka said. “But religion, I don’t believe in religion, because the modern human has to know there is no religion. There is just energy — energy of belief. What you believe, that’s your religion. And it can be whatever. That’s my angle of view.”

Sauer said he first saw a change in Prochazka when the fighter began sermonizing to him and other people close to him about life philosophies.

“He started to talk to me and other friends about how we should live,” Sauer said. “Now, he was a clever guy and started to tell us how we should do this and why this. That was the biggest change. It was like zero to 100, a change of 180 degrees. We didn’t know what was the matter with him.

“He’s living the Bushido way and everything and he wanted his personal friends to live the same or similar. He wanted the people around him to be the same way.”

The guy who once drank booze from a vehicle’s gas line was now preaching a better way to conduct oneself. Prochazka had finally found what he was looking for in life — a way and reason to channel all of his energy into something constructive and civilized. He now reserves all of that inner turmoil for the UFC Octagon, much to the chagrin of opponents. Since that loss to Edilov, Prochazka is 22-1-1 with an incredible 21 finishes.

“It was a full change of myself because I was another person,” Prochazka said. “I’m glad for that. I’m keeping that chaos from the youngest time in myself still. But I want to show it just in the cage. Just to the cage, straight to the victory.”

PROCHAZKA WAS IN the corner of the Rizin ring, waving his arms back-and-forth. It was a few hours before Rizin 20 in December 2019. Other fighters were in the ring, warming up or going through their walk-throughs before competing. The Asakura brothers — Kai and Mikuru — were doing some light sparring. Behind them, Prochazka, the reigning light heavyweight champion at the time, was standing in the corner, motioning like he was running in place without moving his legs.

Kashiwagi, the Rizin matchmaker, said Prochazka would routinely do “weird things” like that during fight week, including meditating in the locker room before walking to the ring.

“I once asked him what he was doing during the ring check and he said, ‘I’m feeling today’s atmosphere and how the ring feels through my body — do you understand?'” Kashiwagi said. “I had no idea how to respond to that.”

Prochazka is quirky, but none of it is without reason. He wears his hair in a unique, high ponytail that has become a signature look. Prochazka said his hairstyle is an homage to a mongkhon, the headpiece that Muay Thai fighters wear during their prefight Wai Kru ritual.

Since 2017, Prochazka has lived in a cottage about 30 minutes outside of his hometown of Brno, near a reservoir. Sauer described it as “the middle of nowhere,” in a forest with no entry road. Sauer said he lives only five minutes away from Prochazka, but if it’s snowing, he can’t drive to his friend’s home due to the lack of roadway. The cottage has electricity and other amenities, including a place to work out and train — which Prochazka calls a “playground” — but no gas. He gets his water from a well.

“I’m just doing what is necessary to be the best,” Prochazka said. “If I have to live like that, think like that and eat like that, I will just do that. Because I want that — that’s all.”

Training has presented some challenges for Prochazka, Sauer said. Despite all those years of fighting in the street, Prochazka has lost any desire to hurt someone who is not his UFC opponent. Sauer said Prochazka has injured his hands and wrists on several occasions because he doesn’t want to tightly ball his fists during sparring so he won’t inflict any undue damage on teammates.

“It’s a little bit weird,” Sauer said. “He doesn’t want to hurt people, but he’s fighting in the most dangerous sport in the world. That’s the change in him.”

Prochazka’s fighting style runs counter to that, and it’s the outlet for his inner chaos, based on this attitude: “attack, not defend — every move must be attacking.” He got caught by several big punches in his last fight against Dominick Reyes in May 2021, but kept moving forward until he landed a spinning back elbow at 4:29 of the second round that knocked Reyes unconscious.

“Some guys, they take that like it’s playing — like MMA is playing,” Prochazka said. “No. For me, I’m taking that like way of [the] warrior. It’s about life and death…. You have to be 100 percent successful if you want to win. If you want to win, that means you can live. If you [do] not, you die.”

But Prochazka is also not afraid of losing. He said he released himself from those fears because this is all part of his journey, regardless of the results. He plans on practicing martial arts — and applying Bushido principles — long after his fighting career is over. The mind, Prochazka said, has to be like a weapon. During a fight, the goal is for the mind to be free and have ideas spring into it, leading to attacks. Prochazka acknowledges he has not gotten to that point yet.

“It’s not simple,” he said. “It’s very hard to achieve that, to be on that level. To be so free and see the things like that…. That’s the way. That’s the way to the mastery. I’m still growing. I’m still working.”

If he beats Teixeira on Saturday, the UFC title would be the next milestone in what has become a lifelong voyage, one shaped by martial arts but one that also contains greater meaning. Hovezak said Prochazka doesn’t want just the belt but “a perfect fight, a perfect martial art — that’s our way.”

“He wanted to reach some mastership or be a master of martial arts,” Sauer said. “Be a master in his life, in his mind. It’s not about the belt, because that’s only one thing. It’s the journey, it’s the way. I don’t know if I want to say a samurai journey, but this is his way of being a master of what he does. The belt is one of the targets. Not the main and only target, but one of the targets.”

And those targets, those goals are driven by the words of Musashi, written nearly four centuries ago.

“The book is a guide for us and we create our own strategy,” Hovezak said. “I believe that after years Jiri will write a similar book according to which the new fighters will follow.”