A nylon curtain splits the gymnasium along the half-court line at the YM-YWHA of Union County, N.J. Fathers and sons wearing yarmulkes walk to the far side of the court, basketballs tucked under their elbows, ready for a light shoot-around. On the other side, Coach Sandy Pyonin is deep into a five-hour workout with Tyler Roberson, a 6’8″ senior power forward at Roselle Catholic High School, and the 27th-best basketball recruit in America for the Class of 2013, according to ESPN.Roberson, his shirt soaked with sweat, finishes off a dribbling drill with a powerful one-handed dunk—one of those plays that only truly gifted athletes can complete, where gravity slows down for an extra tick. Nevertheless, the dribbling is sloppy. Pyonin steps onto the court, with his arms folded: “I don’t need the dunks or all that other garbage,” he explains matter-of-factly. Without a word, Roberson jogs back to the top of the key to repeat the drill. This time, he doesn’t dunk.Roberson is Pyonin’s prized prospect. They’ve been training together for four years, and they make an odd couple. Sandy is short, blond, white, talkative, and Jewish; Roberson is tall, black, quiet, and goes to a Catholic school.It’s Nov. 23, and late fall is the calm before the storm of the high-school basketball calendar, a short period before tryouts when players typically rest their bodies to prepare for the grueling early-morning practices to come. Roberson, however, is spending most of his time at the Y with Pyonin. Once the season starts, Roberson, who recently committed to Syracuse University after fielding offers from Kansas and Villanova, will go back to Roselle Catholic and Pyonin will return to Golda Och Academy, the private Conservative Jewish day school where he teaches phys. ed. and runs the basketball program. Sandy may train Roberson on off days, but their regular workouts won’t resume until March.Like other top high-school coaches, Pyonin has racked up impressive career achievements in his 40 years as a coach, including three National Amateur Athletic Union (AAU) Championships, two New Jersey Prep B State Championships, two International Maccabiah Gold Medals, more than 2,300 AAU victories, and more than 570 varsity wins at Golda Och Academy.But with Pyonin, legacy comes down to one number: 34. That’s the number of his players who have made it to the NBA.It’s one of the most accomplished high-school coaching résumés of all time. And yet outside of the AAU basketball community, Pyonin is virtually unknown. He doesn’t even have a Wikipedia page. What this coach from a small yeshiva does have, though, is a legion of fans in some of the best basketball players to emerge from New Jersey in the last 40 years.“Anything I could do for Sandy, it’s not enough,” Edgar Jones, Pyonin’s first prospect to make the NBA in 1980, told me. “He’s touched so many lives, not just the ballplayers, but the people around the ballplayers, the families of the ballplayers.”***Pyonin grew up in Elizabeth, N.J., during the ’60s and ’70s in a Conservative Jewish household. He was always athletic and went on to play soccer and lacrosse at Kean University, but basketball was the sport he focused on the most, regardless of his aptitude. “When I was in 6th grade,” he recalls, “I got kicked out of the gym, because I couldn’t really reach the basket. The coach told me to play baseball.”His coaching origin is Jordanesque, a story built on obsessive hard work meant to prove people wrong. After getting cut from his high-school team in his sophomore and junior years, Sandy trained harder, practicing 10 hours a day on a backyard hoop, studying games on television. He served as player-coach on teams with his friends and taught the game to himself until he received coaching offers at age 19.“I had better knowledge of the game than the NBA coaches, in my perspective,” he told me. “They didn’t know how to screen around the foul line, they didn’t know how to screen on the jump ball … they still don’t know how to do that in the NBA today, to get that extra inch. I guess they don’t think it’s that important.”When you watch Pyonin coach his players on a basketball court, you realize everything is important. Every inch, every dribble, every movement has a purpose. And with the proper guidance, every player can improve.My father was one of those players, a 12-year-old shooting at the Y in 1968, when they met. Pyonin was just out of high school, getting serious about coaching. “I’d never spoken to him before,” my father remembered. “He just came up to me and asked, ‘Do you want to become better?’ ”Their relationship continued as Sandy began developing his philosophy with the YMHA Roadrunners, a squad of Jewish high-schoolers who played on weekends in the early 1970s. “Sandy stressed the conditioning. He always wanted you to play hard, to play smart, and play as a team. If guys didn’t focus, they had to run laps.”Forty years later, Pyonin maintains excellence with the same gritty philosophy even as basketball has evolved into a sport full of flashy highlights. His approach has paid off: Kyrie Irving, Cleveland Cavaliers point guard and 2011 NBA Rookie of the Year, trained with Sandy for four years. Orlando Magic forward Al Harrington, a 14-year NBA veteran, spent his high-school summers with Sandy. Utah Jazz guard Randy Foye started with Sandy as a 7th grader, and Sandy still calls him after every game. Remarkably, none of Pyonin’s elite players were charged for the years of training sessions and mentoring. “I never charge any player who can’t afford it. I believe in the Robin Hood philosophy—steal from the rich and give to the poor.”“Without Sandy in my life and without Sandy helping me through college, through high school … I wouldn’t be here now,” Randy Foye has said. “After every game I play in the NBA, no matter if I have 30 points or if I have five points, Sandy’s calling. And he’s saying … ‘I just want you to know that I love the way you played D, I loved the way you passed.’ ”Continue reading: How Pyonin works his playersDespite this devotion, Pyonin remains largely unknown on the national scene. To put this in perspective, consider that Sandy’s closest contemporary is Bob Hurley, Sr., head coach of St. Anthony High School in Jersey City. Hurley has more than 1,000 varsity wins and was inducted into the Basketball Hall of Fame two years ago. The lack of Sandy’s fame is partly the result of his day job at Golda Och. He doesn’t recruit players to the school, and due to his players’ daily religious obligations, he usually practices with the varsity team once per week, which is an unheard-of limitation in today’s specialized scholastic sports culture. Yet he stays committed to his students and teaching responsibilities.“What makes Sandy so special is his dedication, passion, and tireless work ethic. He devotes the same energy to every student as he does his AAU and NBA players,” Joyce Raynor, the head of Gold Och Academy, told me. In September, Golda Och held a ceremony to rename their basketball court the “Sandy Pyonin Court.” When Sandy took the podium for his speech, he said, “I wanted to give back to Jewish youth. I was offered many, many jobs, I could’ve been coaching in the pros, but I’m still here.” He says he’s turned down job offers from Duquesne University and the Boston Celtics over the years.While Pyonin isn’t particularly religious, through his coaching and teaching he’s managed to become a role model in a Jewish community that usually doesn’t prioritize athletics. And regardless of how often he attends synagogue, his commitment to his players is something religious in the sense of devotion to a positive cause.That’s not to say that Pyonin is overly modest or unambitious: He calls himself “the best trainer in the world” and thrives on the challenge of working with players who may not be headed for the pros. “Give me a guy who isn’t a superstar,” he said. “Let’s get in the gym and really work for a few months, and I guarantee he’ll be able to compete against the best.”***While most coaches concentrate on the number of wins and championships they accrue over a career, Pyonin values the ability to build up a player from scratch, developing mental and physical toughness. A lot of prospects have the talent to succeed, but not the work ethic. Pyonin just works his players harder than anyone else, making sure they turn weaknesses into skills.Former players regularly use the word “crazy” to describe their coach—crazy as in ridiculously focused, intense, and fanatical. Zack Rosen, point guard for Hapoel Holon of the Israeli Super League, trained with Sandy from 2003 to 2005. “ The guy knows the game and he knows how to work you. He pushes you every day.” Before joining Hapoel Holon, Rosen had an accomplished career at the University of Pennsylvania, winning Ivy League Player of the Year in 2012 and earning a spot on the Philadelphia 76ers Summer League roster after graduating. Rosen believes Pyonin helped him develop a strong work ethic in those early years at the Y. “Sandy loved August and September,” he said. “Those were the times when there weren’t really any tournaments and you could just work all day. That’s the huge secret to being successful—just work that much harder than the other guy. He gives guys focus and makes them work. Simple formula.”In return for that formula, Pyonin requires that they devote enough time to get better. “I wanted to see if they’d come on a consistent basis every day,” Pyonin said. “If I left them for 20 minutes, we’re they still doing that drill? Or would they leave, or would their minds wander?”The session with Roberson begins with a series of dribbling and shooting drills meant to develop a versatile skill set he can bring to Syracuse. Where Pyonin really excels is letting Roberson practice those skills in game situations. During four-on-four pickup games at the Y, Sandy teams with Roberson and tells him to dribble with his left hand or use a certain move against live defense. It’s a subtle way Pyonin can still coach his players in unplanned scenarios.Players come into the Y already knowing about Pyonin’s demanding reputation, including the one-on-one games to 100 he plays against his top prospects; even in his mid-60s, he plays pickup games for hours at the Y. But they’re also aware of Pyonin’s unwavering loyalty to his players who put in the effort.Edgar Jones began training with Pyonin in 1974, when he was just a raw 6’10” kid from Newark who played basketball only because of his height. Pyonin helped him land a scholarship to the University of Nevada, Reno, and after he set the school’s scoring record, the Milwaukee Bucks drafted him in the second round of the 1979 NBA Draft. However, the Bucks cut Jones the day before the 1979 season started for being too slow, and he came home thinking his career was over for good.“I didn’t want to play basketball anymore,” Jones says. “I just stopped playing. But Sandy kept calling me and finally got me back in the gym.”“I trained him every day,” Pyonin recalled. “I’d bring him to the Y at 10 p.m. We ran laps and laps and laps, and at first he couldn’t keep up with me. But eventually he got in shape, and then I couldn’t keep up with him, because it took me five strides to keep up with one of his strides.”After the workouts, Pyonin talked to Jones about the mental toughness needed to break into the NBA. “Sandy taught me how to play smart basketball.” Jones said. “He explained to me why we did the drills and how I should think on the court, because up until that time I primarily relied on my athleticism.” The pair would shoot pool and eat White Castle. Sandy kept kosher back then, only ordering fries and soda.The exhausting practices paid off. Eventually, Jones played for the Lehigh Valley Jets of the CBA. The following year, the New Jersey Nets signed him. He played six seasons in the NBA with the Nets, Detroit Pistons, San Antonio Spurs, and Cleveland Cavaliers. He averaged 9.0 points and 4.8 rebounds per game for his career and was a participant in the 1984 Slam Dunk Contest.When Jones played in New Jersey during the 1981 season, Pyonin drove to all 41 home games to support (and coach) his first star pupil. “I could hear his voice in the stands when I couldn’t hear anybody else,” Jones said.It’s a view echoed by Roberson, Pyonin’s newest protégé. Roberson is incredibly shy and gives mostly short, respectful answers to my questions. However, when I ask the 18-year-old high-school star to identify an area Pyonin could improve on as a coach, he thinks for a few beats before offering: “Some players might be intimidated by him. Players may have left or thought about quitting because of how intense Sandy is, but I don’t think that’s something that he needs to work on. I just think that’s who he is and why his players are so much better.”***Like this article? Sign up for our Daily Digest to get Tablet Magazine’s new content in your inbox each morning.Jordan Teicher is a writer living in New York.