Kawaguchi, Japan(CNN) It's a rainy Sunday morning in Kawaguchi, a city of around half a million people on the outskirts of Tokyo. Men and women toting Japan's ubiquitous clear plastic umbrellas file into the entrance of a nondescript corner bar.
The sign above the door reads June Bride. For 25 years, it was a popular watering hole in this quiet residential neighborhood in Saitama Prefecture.
Tucked on a street corner, the exterior of June Bride has changed little over the years. But inside, the place has undergone a drastic transformation. The old bar and karaoke stage are gone, replaced by a pulpit adorned with a large cross. Neat rows of chairs slowly fill with damp but mostly smiling faces. They chat silently amongst themselves.
While some faces in the crowd are longtime bar patrons, they no longer come here to drink. This is, without a doubt, a place of worship.
One of the last people to enter the room is the man everyone calls teacher, Sensei Tatsuya Shindo.
From the moment he walks through the door, parishioners forget the dreary weather as electricity fills the room. Shindo takes command of the pulpit -- raising his arms, nodding his head, and preaching with intensity as if he is pulsating with "energy from above."
Shindo is 44 but looks much younger, partially because of his long hair and also because he seems to have a permanent grin. He laughs often, even when speaking about the dark past he shares with many members of his congregation of around 100 people.
"Before, we were in rival gangs, firing guns," he exclaims from the pulpit. "Now, we're praising the same God."
Inside Japan's murky criminal underworld
The pastor, like some of his parishioners, is an ex-gangster. Most of them were teenagers when they joined the Japanese mafia, known as the yakuza. Shindo was 17.
"I was a child. I didn't think too deeply," he says. "And I admired the yakuza for what was visible only on the surface. They have lots of money, spend their money lavishly, and play glamorously. The bad guys looked so cool in my eyes."
The intoxicating illusion of an easy life of crime has lured tens of thousands of Japanese teenagers to join the yakuza. Shindo says most of his fellow gangsters came from dysfunctional families. The yakuza fostered a sense of loyalty and brotherhood. But as Shindo fell deeper into the Japanese underworld, he learned the price of belonging was often paid in blood.
"My boss was killed. People were killed in power struggles. People's legs were shot. A guy who was doing drugs with me died of intoxication. Suicides happened. Sudden deaths. I've seen many deaths," Shindo says. "I saw my henchmen get stabbed to death."
Shindo's body bears the scars of his old life. His chest and arms are covered in intricate tattoos, the telltale symbol of mafia membership in Japan. In an effort to exclude yakuza members from society, visible tattoos are forbidden in most public places. He often removes his shirt when baptizing other tattooed ex-gangsters.
He became addicted to crystal meth. He drove under the influence and crashed his boss's car. He shows off his missing pinkie, which was cut off with a chisel in a yakuza ritual of atonement for the transgression.
Shindo was arrested seven times. He went to prison three times, beginning at 22. By the time he was 32, he had been excommunicated by the yakuza after spending about 8 of 10 years as an inmate. He says he found God while reading the bible in solitary confinement. He studied and became a preacher after his release more than a decade ago.
Today, Shindo leads a growing congregation from all walks of life.
"A lot of people with different backgrounds come here. Those who are divorced, bankrupt and cast away. There are also parents who have missing children, those whose sons are put into jail, or those who've been abandoned after prison. This is a place to restart your life," he says. "A yakuza returning to society is indeed extraordinary."
One of the newest members of the congregation is former yakuza member named Hiro, who ran away from Japan's largest crime syndicate the Yamaguchi Gumi after after five years.
"It's really hard to get back to normal society," he says.
The 37-year old has been shunned by his family and lays down a thin mat each night to sleep on the church floor. A fellow worshipper hired him as a painter.
"The life I had in the past, I never woke up in the morning as early as I do now. I lived just to earn money. To get money, I did bad things and sold drugs as well. But my new life is the important phase for me to become a better person. I changed a lot after coming to this church," he says.
Hiro believes if he didn't have the church, he'd already be back in jail. He says this is a rare chance to transform his life, in a society that doesn't easily give second chances to people like him.
Ex-mobsters don't have many options in Japan. Their secretive underworld is shrinking and profits are drying up from years of government crackdowns. Today, police estimate there are around 50,000 yakuza -- down dramatically from just a few years ago.
Jake Adelstein, an author and journalist in Tokyo who has written extensively about the yakuza, says the Japanese mafia keeps thugs in check. He says if the yakuza lose influence, street crime could surge in Tokyo, considered the world's safest city.
"They're going to have to find a way to use these people. And they're going to have to find a way to remove this stigma of being an ex-yakuza," Adelstein says. "These guys, when they leave, they are going to petty crime, going to jail, or killing themselves. A lot of them commit suicides. Because, Japan isn't a very friendly place to people who have missing fingers and covered with tattoos and who've never worked in honest ways in a lot of days in their life."
In his new role as sensei, Shindo has baptized about 100 people including his mother, Yoshimi Shindo, who proudly watches her son preach each Sunday.
"When he came back [from prison], he apologized and said, 'I survived for you, mother.' When I heard those words, I decided to forget everything that happened in the past. And now, I'm very happy," she says.
When her son needed a space for Sunday service, she gladly offered June Bride, the bar she owned and ran for a quarter century. In the early years, fewer than 10 people attended Sunday service. Now, the room is routinely filled with dozens of people each weekend.
"I think this place has significance that God provided here for us. I believe it was God's intention," she says.
She laughs that her son is called sensei, considering the tumultuous path that brought him here. June Bride is no longer a place for cocktails and karaoke, but the room is filled music each weekend as dozens of voices sing upbeat Christian songs.
"I believe my son's life portrays God's surprise ending," she adds.