There are four world titles in each of boxing’s 17 divisions. Any attempt to clear up just who “the man” or “the woman” is in a given weight class is a boon to the sport, and that’s what makes Saturday’s fight between Jermell Charlo and Brian Castano for the undisputed junior middleweight championship so special.

Not only is it an excellent matchup in its own right — a style clash that pits a boxer-puncher against a pressure fighter — the Showtime main event will settle supremacy at 154 pounds. All four belts are on the line, as Charlo holds three and Castano holds one heading into the fight.

The winner will emerge as undisputed champion, a distinction that just two men and three women in all of boxing can boast right now. Within the past year, Josh Taylor (May 2021), Teofimo Lopez (October 2020) and Claressa Shields (for the second time, in March 2021) Jessica McCaskill (August 2020) became undisputed, with Katie Taylor (March 2019) also holding an undisputed crown.

Lopez’s status is disputed by some, even though he seemingly won all four belts fair and square. That’s because the WBC designated Vasiliy Lomachenko the “franchise” champion before his title fight against Lopez, with Devin Haney getting upgraded from interim to full WBC lightweight world titleholder status in the process. WBC president Mauricio Sulaiman insists that Lopez is indeed the undisputed champion, yet confusion persists.

It’s just another example of why boxing badly needs more clarity, and why more fighters and key figures in the industry have been moving toward more unification fights in recent years. The proliferation of titles has helped sink boxing’s popularity from a sport that reaches people from all walks of life around the globe to one that often appeals to only the most hardcore of fans. Even those who are supporters of the sport will have trouble telling you who the best boxer is in a given division.

If boxing is going to continue to gain relevance in a jam-packed sports marketplace, it will need more fights in the mold of the PBC-promoted Charlo-Castano and the clarity that the champion who emerges Saturday in San Antonio will deliver.

“If we can get to a point where each division has one champion, then we’ve really cracked it,” Matchroom Sport’s Eddie Hearn told ESPN. “Network and governing-body politics combined with egos make this doubtful, so when we get [undisputed title fights], we need to really celebrate them.

“The fragmentation of belts is too confusing for a casual fan. The more unification and undisputed fights, the better.”

Hearn has delivered two undisputed title fights over the past couple of years, both women’s matchups: the 2019 battle between Irish star Taylor and Delfine Persoon, and the 2020 fight between McCaskill and Cecilia Braekhus. Matchroom promoted the rematches, too.

Of course, it has proved far easier to bring these undisputed title fights into existence between women thanks to other problems surrounding the sport. Because women in boxing are typically paid much less than their male counterparts, they feel a more pressing incentive to cash in as much as possible on big fights.

“To become the undisputed champion means everything to me because it’s a goal that I’ve always worked for, since the days I was sweeping the sidewalks of my neighborhood to get some money on my family’s table.”

Brian Castano

One of the biggest stumbling blocks in pairing some of the bigger names in men’s boxing is that crossing promotional borders can be tough. Many fighters don’t feel much pressure to risk their titles or pristine records to chase being undisputed.

“The plethora of champions, often undeserving, have weakened our product and the quality of boxing,” said Lou DiBella, who spearheaded HBO’s boxing programming throughout most of the 1990s. “It’s critical that we have undisputed champions so that the public can identify who the best is. Maybe that way, our champions will once again be significant in pop culture and their influence.”

Thankfully, if the past couple of years and the attitudes of certain fighters are any indication, that freeze on big unification fights is starting to thaw.

For a few weeks, it appeared Hearn had sliced through the political divide to deliver the biggest undisputed title fight of them all: Tyson Fury vs. Anthony Joshua. Hearn, who promotes Joshua, and Fury’s side, promoted by Top Rank, agreed to terms for a clash for all four belts on Aug. 14 in Saudi Arabia. This would have been the first time a heavyweight fight with those stakes would’ve happened in the four-belt era.

However, an arbitrator presiding over the Fury-Deontay Wilder rematch dispute ruled in favor of Wilder, enforcing a third fight. Joshua, in the meantime, will defend his three titles against former undisputed cruiserweight champion Oleksandr Usyk on Sept. 25 in London.

If Fury and Joshua win, they will once again be on a collision course to unify all four belts. But a loss by either man would send another opportunity to present clarity by the wayside, leaving the heavyweight division in the same position as so many others that struggle to point to a true No. 1.

“I believe Fury-Joshua will eventually happen because it needs to,” DiBella said. “But there are way too many fights that need to be made that haven’t been made. As long as there are what’s tantamount to three leagues [Top Rank on ESPN, Golden Boy and Matchroom on DAZN, PBC on Fox and Showtime], there will be a lot of impediments and a lot of frustrated fans going forward.”

There’s potential for more undisputed champions in the near future. In men’s boxing, there are currently six unified (not undisputed) champions, boxers who hold more than one world title in a division. Beyond Joshua, Artur Beterbiev holds two titles at 175 pounds; Canelo Alvarez has three belts at 168; Errol Spence Jr. has two at 147; Murodjon Akhmadaliev holds two at 122; and Naoya Inoue currently owns two world titles at 118. On the women’s side, Amanda Serrano has two titles at 126 pounds, Shields has all but one of the world titles at 160 pounds and Elin Cederroos has two world titles at 168.

Of that group, only Alvarez seems to be on track to continue the unification trend by the end of 2021. He’s attempting to finalize a Sept. 18 bout against Caleb Plant that would crown an undisputed super middleweight champion.

Canelo’s goal for some time has been to collect every title in every division he fights in. He fell one belt short of his mission at 160 pounds. At 168, where there has never been an undisputed champion in the four-belt era, he needs only Plant’s title.

“It’s making history for me, because it is difficult to do and there’s a reason why nobody has done it,” Alvarez said earlier this year.

Charlo and Castano will be vying for similar status on Saturday in San Antonio, just a few hours away from the unified champion’s hometown, Houston.

With a convincing victory over Castano, Charlo would likely crack boxing’s pound-for-pound top 10. The 31-year-old regained the WBC title with a knockout of Tony Harrison in a December 2020 rematch, then added two more belts with another KO, this time against Jeison Rosario last fall.

For Charlo, the efforts of others to unify their divisions has not gone unrecognized, and he’s after the same kind of validation.

“I see they tried to [unify titles] in the heavyweight division,” Charlo (34-1, 18 KOs) said. “It’s bringing excitement, especially with how Josh Taylor did it against Jose Ramirez. That’s what 2021 seems like it’s about.”

The more fighters who have made an undisputed championship their highest priority, the more the idea seems to pick up steam. It’s a far cry from the way the career of Terence Crawford, the No. 2 pound-for-pound fighter in the world, has played out since he unified the junior welterweight titles in 2017. He won the WBO belt in his first fight at welterweight in 2018, but thus far he hasn’t been able to entice another champion into the ring.

Charlo’s perception is that some of the blame lies at Crawford’s feet, that the onus is on the fighter to demand the biggest matchups — much like Charlo did following Castano’s title-claiming effort against Patrick Teixeira in February.

“The boss is the boxer,” Charlo said. “[The promoters and managers] shoot all these names out to you. You look at the names, you look at the records; you pick the best one. That’s what me and my brother [Jermall] did. We try to pick the best one rather than pick the worst one.

“It makes so much sense stepping up for yourself and being who you should be, and not allow these people to control y’all’s destiny.”

When he meets Castano on Saturday in a bout he’s only slightly favored to win — a rarity in boxing — Charlo understands the stakes. Score the victory and reign supreme at 154 pounds; enjoy all the riches that accompany that rarefied status. Lose, and at least you go down fighting for what you believe in.

For a fighter like the Argentine Castano (17-0-1, 12 KOs), who has yet to gain recognition stateside, the battle for all four belts is about far more than boxing: It’s a lifelong dream envisioned in the struggle thousands of miles away, and a chance for immediate elevation into the boxing world’s collective consciousness.

“To become the undisputed champion means everything to me because it’s a goal that I’ve always worked for, since the days I was sweeping the sidewalks of my neighborhood to get some money on my family’s table,” said Castano, 31, who drew with former champion Erislandy Lara in his most high-profile bout.

“It would be tremendously meaningful for Argentina’s and Latin American’s boxing legacy, as there was never an undisputed Latino champion with four belts. … As a former fighter himself, my dad introduced me to boxing in the days of the [Marvin] Haglers, the [Sugar Ray] Leonards, the [Tommy] Hearns and the [Roberto] Durans, when they fought each other and everybody was excited about it. So I think it’s great for boxing that the champions face other champions. That’s what people really expect. And that’s what every real champion wants in order to test themselves.”

The days of the Four Kings of the welterweight division are long gone. For one night, though, Charlo and Castano will throw it back to the ’80s and yesteryear, fighting for far more than seven-figure purses.

They’ll vie for legacy, of course, but also, perhaps, they can help remind everyone what made boxing so great in the first place, and help continue to usher in a new golden era along the way.