“He’s come a long way from when we were just trying to get a consistent form and make ’em from the free throw line,” said Otto Porter Jr.’s mother, Elnora Timmons Porter. (Katherine Frey/The Washington Post)

Mom taught Otto Porter Jr. how to shoot. Of all the gifted southeast Missouri players named Porter or Timmons — the two royal basketball families of that area — Elnora Timmons Porter influenced her son’s now-esteemed jump shot the most.

They stood on a paved slab in their back yard and went through the basics. Elnora taught young Otto, about 8, how to position his hands. She told him to focus on the rim and to see the ball roll off his fingertips. She emphasized the follow through and hold. Her husband, Otto Sr., would come home and worry about footwork and using the legs. Mom kept it simple.

“I just had one thing in mind,” Elnora said, laughing. “I just wanted him to hold it and shoot it right. He’s come a long way from when we were just trying to get a consistent form and make ’em from the free throw line. A long way.”

Now 23, Otto Jr. is one of the most efficient scorers in the NBA. His range extends well beyond the free throw line. The Washington Wizards small forward has grown from a rookie who made just four three-pointers in the 2013-14 season to the league’s fifth-most accurate deep shooter, at 43.4 percent. The improvement has transformed him from a versatile player slowly finding his way as a pro to an invaluable NBA commodity: a shooter with a diverse skill set.

This summer, when Porter will be a restricted free agent, he could command $100 million for his combination of skill, hustle, basketball smarts and knack for making winning plays. But for now, he’s focused on helping the Wizards advance past the Boston Celtics in the Eastern Conference semifinals. Although his three-pointer isn’t falling, Porter is shooting 57.1 percent in three games this series. He’s averaging 16 points and 9.3 rebounds.

[Wizards-Celtics Game 4 preview: Can Washington tie it up?]

It’s typical Porter, producing without hogging the ball, running all over the court, scoring at the rim, from midrange and from deep despite the Celtics’ determination to eliminate his clean three-point looks.

“Whenever he was in school, he never shot out on the three-point line,” Elnora said. “Whenever we’d been in the postseason, in the regionals or state, then he’d start shooting them. I always told him, ‘If you ever go to the NBA, they’re going to be looking for players to shoot the three.’

“I’m glad that he’s improved on his three. He needs to start shooting more. But how far he’s come, it’s just a blessing because when he first got to the NBA, he was saying, ‘Mama, when is it going to be my turn?’ I said, ‘Boy, just hold on. God will let you know.’ Now, it’s his turn. So he’s busy making something of it.”

[That fire Brandon Jennings fueled in Game 3? It started in Compton.]

Elnora was born into a hoops clan, and then she married into another one. When the conversation shifts to the dribbling genes of her joint family, she likes to keep quiet and let the focus remain the grand accomplishments of Senior and Junior, and her brother, Marcus Timmons, and the dozens of relatives who have helped Scott County Central High School win a Missouri-record 18 boys’ state championships and six girls’ titles. But Mama could hoop, too. She earned all-state honors in 1985. And she had a reputation for releasing her smooth jumper at critical moments to win big games.

“She doesn’t talk about herself a whole lot, but then you hear the stories,” Otto Jr. said. “And you’re like, ‘Wow, that’s pretty cool.’ ”

On the weekends, Otto Sr. would take his son to the local YMCA and instruct him to perform drills while the father exercised. But during the week, the mother oversaw his development. The rules were clear: Do your homework. Get your shots up. Then you can move on to something else.

After a while, the routine was so ingrained that Elnora and Otto Jr. could share a look and know the task had been completed.

The son loved the structure. The older he got, the more he added to his routine. Many nights, Elnora and Otto Sr. would look outside after dark and see Otto Jr. shooting under the glow of an outdoor lamp.

“I wanted to be like Allen Iverson,” Otto Jr. said, which is funny because, at 6 feet 8 and having learned to play so well without the ball, his game is nothing like his idol’s style.

To Elnora, Otto Jr.’s jumper still looks like the one she taught him. He has adjusted his mechanics as his body changed and as the level of competition improved, but she recognizes the shot. Elnora coached him to be practical; Otto Sr. worked more on perfecting his game. She just wanted to show a growing young boy how to put up a shot that could go in. She just wanted to give him something that he could repeat. The hallmarks of that approach definitely remain, even if the jumper has changed a little.

For an elite shooter, Porter doesn’t have picturesque form. It’s not the perfect, quick release that Klay Thompson has. It doesn’t possess the enviable fluidity of Bradley Beal’s shot. When Porter catches a pass, he’s slow to gather the ball and get into his shot. It gives the defense time to close out on him, but because he has long arms and shoots a true jump shot, defenders don’t affect him much. His left hand, his off hand, is more on top of the ball than preferred. But his release is just as clean and smooth as any of the great shooters. His follow through and hold are ideal. Porter also shoots the ball the same every time, and he rarely takes bad shots.

“It’s as consistent as I’ve seen,” Wizards Coach Scott Brooks said.

Said Porter: “I’ve played basketball for a while now, and I know what are good shots and what are bad shots, and for me, I don’t like taking bad shots. I’m always make sure that I’m square to the basket and making sure I get a lift off the floor, making sure that I just stay to my mechanics. Follow through. Hold it. The small details. Making sure I get off the floor when I jump. You don’t want to shoot anything flat-footed, stuff like that. Making sure I stay straight up and down. No fade, or anything like that.”

Elnora watches her son closely. She knows when he’s nervous; he tugs on his jersey, same as he has done since middle school. When he gets to his favorite spots on the court, she can envision the shot swishing before he even shoots it.

It looks the way it did 15 years ago. And as the ball falls through the net, there’s her boy, all arms and legs to this day, holding his right arm in the air, keeping it aloft like a serious shooter. Like a Porter and a Timmons. Like Mama taught him.

For more by Jerry Brewer, visit washingtonpost.com/brewer.