Three players in the history of the NBA have recorded 25 points, 10 rebounds and 5 assists in a Game 7 before the age of 25: Jerry West, Kobe Bryant and, as of last week, Jayson Tatum. The first guy is immortalized as the league logo, the second became one of the most revered basketball icons of the 21st century and the third is a 22-year-old leading a decorated franchise into the conference finals on Tuesday night (6:30 p.m. ET, ESPN).

The Boston Celtics are back in contention, and Tatum's play is a big reason why. It's been clear for a while that Tatum had the potential to become one of the finest scorers in the NBA. But his recent playoff performances prove he's turning into something much more than a scorer with glitzy stats.

Just look at his recent defensive numbers: According to Second Spectrum tracking data, 97 players have recorded at least 250 half-court matchups on defense this postseason. Tatum ranks first in effective field goal percentage (eFG) allowed at 38.4%.

Considering he just spent seven games checking the defending champs, that's pretty impressive. Whether it was hounding Kyle Lowry, stifling the Toronto Raptors' 3-point shooters or crashing the paint to grab the most important free throw rebound of 2020, Tatum is much more than just a bucket. He is rapidly developing into one of the most complete superstars in the NBA.

It's a remarkable leap. Just last season, Tatum's development arc looked stunted in a sophomore slump. His scoring volume barely moved from his rookie season, and his efficiencies from both 3-point and 2-point range regressed. The Tatum hype train slowed down like a rickety Green Line trolley ambling its way down Commonwealth Avenue.

But then Kyrie Irving left, Kemba Walker arrived and Tatum spent most of 2019-20 as a third-year supernova. One of the most dangerous young scorers in the game is also taking shape as a well-rounded force. And drilling down into the numbers, three specific developments fueling his leap stand out.

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1. The shot diet

Tatum has always been a marvelous prospect, but this season all that potential morphed into reality as his efficiency numbers exploded with more considered jump shots.

In his first two seasons, Tatum's shot diet was a blast from the past. He feasted on too many unhealthy midrangers, and his overall efficiency numbers suffered for it.

Last season, Tatum took 27.7% of his shots in the midrange, and his eFG of just 37.7% on those tries depleted his overall shooting marks. This season, he took just 17.9% of his shots in the midrange, instead migrating outward to 3-point land.

As a result, his eFG on jump shots went from a below-average 46.7% last season to an above-average 54.7% this season.

Midrange jumpers are important for big, shot-creating wings. In key moments of close matchups, sometimes they're the best looks you can get. Tatum knows he can't completely excise these looks from his repertoire, but he's helped his game by valuing the best possible alternatives.

2. Self-created 3s

It's hard to overstate just how important Tatum's increases in 3-point activity have been to his scoring success.

Last season he ranked 84th in the NBA in total made 3s. This season he soared to 11th. The story of that specific improvement explains a big part of Tatum's leap forward.

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Any young shot creator hoping to dominate this league in the 2020s must have a 3-point arsenal, and Tatum now owns a ferocious one. He combines perimeter volume, efficiency and unassisted shot creation from deep as well as any other rising star in the league. Not only was Tatum one of just eight NBA players to average more than seven 3-point attempts per game and hit at least 40% of them, he was by far the youngest player in that group, too.

(He has become especially dangerous from the left side. Out of 99 players who tried at least 100 3s from the left wing and left corner this season, Tatum's 48.9% conversion rate ranked second, trailing only Joe Harris).

And it's how Tatum is finding these shots that should get Celts fans most excited. He is becoming one of the most self-sufficient 3-point marksmen in the NBA. When you factor in his youth, his size and his ability to create his own 3-point looks, Luka Doncic is really the only contemporary comparison who comes close.

As NBA players and teams continue to chase new ways to increase perimeter production, the most dangerous scorers are now able to create their own 3-point shots. Thanks to players such as Damian Lillard and James Harden, unassisted 3s are among the fastest-growing shots in the league.

Back when the league started its tracking system in 2013-14, NBA teams took only 4.4 unassisted 3s per 100 possessions. This season, that number ballooned to 7.8. That's a 77% bump in just seven years, but that increase owes heavily to a small crop of elite players who are not only great ball handlers and great shooters. They also are able to meld those two skills into seamless acts of self-sufficient shot creation from long range.

These kinds of on-ball 3-point savants didn't even really exist 10 years ago. Now they are taking over the league, and the ability to hit triples off the dribble is emerging as one of the most coveted skills for NBA superstars.

With that in mind, if you had just one way to capture the nature of Tatum's leap over the past two seasons, it might be this:

• In 2018-19, Tatum made 30.7% of his 62 unassisted 3-point shots.

• In 2019-20, he made 41.1% of his 246 unassisted 3-point shots.

His volume increased by nearly 400%, but his efficiency still jumped by more than 10 percentage points.

That's the leap in a nutshell, and regardless of how this postseason ends, Boston fans should be ecstatic about Tatum's sudden increases in this exact scoring category.

Out of 16 NBA players who tried at least 200 unassisted 3s this season, nobody was more accurate than Tatum, who sank 41.1% of them. How good is that? In 2018-19, Stephen Curry led the NBA by sinking 40.9% of 291 attempts.

Curry became the most influential shooter in NBA history by merging handles and 3-pointers in unfathomable ways. Tatum was finishing high school the season Curry made 402 3s. He was at Duke when Curry and the Golden State Warriors won 73 games. He's been getting ready for this. This dude might actually be on track to become the best jump-shooting forward since peak Kevin Durant.

Harden and Doncic attempted more step-back 3s this season. If you watch those guys -- who both launched more than twice as many as Tatum -- it's clear Tatum's next step toward bigger scoring numbers can come via more isolations and even more unassisted triples. This Eastern Conference finals matchup with the Miami Heat gives him another chance to show off those skills.

3. Freebies

Tatum has transformed from a player who shied away from contact in the paint to one who now realizes that contact is just a synonym for easy money.

Over the past year, Tatum has embraced the dark arts of whistle-hunting, and it's paid off. Last season, he took only 2.9 free throws per game. This season that number jumped to 4.7 -- and it has surged even more in the playoffs, as Tatum is taking 7.2 foul shots per contest.

Out of the players remaining in the postseason, only Jimmy Butler, Anthony Davis, LeBron James and Kawhi Leonard are going to the line more than Tatum. Like it or not, free throws are the currency of superstars, and seeing Tatum's name with those guys is yet another indicator that Tatum has checked into first class.

Whether you look at his volume, his efficiency, his shot selection or his ability to get to the line, it's hard to come away thinking anything except that this guy is ready for his close-up. Miami will challenge him. Jae Crowder, Butler and Bam Adebayo will force him to embrace all of those improvement areas, and they'll stretch his still shaky playmaking.

Almost all season, Tatum has looked like a two-way superstar wing who can do it all and get buckets in the clutch. With a trip to the NBA Finals on the line against a team that just shut down the reigning MVP, this is his moment.

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