The NHL logo spun around before locking into place, with a sound effect reminiscent of a cell door locking. The next image on the video was that of the new sheriff in town.

"I'm Brendan Shanahan, the National Hockey League's senior vice president of player safety ..."

Shanahan was 42 years old in 2011. He had retired from a Hall of Fame career two years earlier, taking a job with the NHL. In June 2011, he helped create the league's first Department of Player Safety. It wouldn't just hand out suspensions to players but, in a revolutionary move, would show its work through explanatory videos like this one.

"Friday night in Minnesota, an incident occurred in a game between the Columbus Blue Jackets and the Minnesota Wild ..."

As the video showed, defenseman James Wisniewski of the Blue Jackets delivered a high hit on Wild forward Cal Clutterbuck after the horn sounded to end the period in a preseason game on Sept. 24, 2011. The hit was late, intentional and from a repeat offender. But Shanahan noted something else about the hit: Wisniewski had violated Rule 48.1 for an illegal check to the head, a recently added regulation.

Wisniewski was suspended for 12 games. The rest of the league was on notice. Targeting the head-on checks would no longer be tolerated.

"If you're a great player with great timing, you could still deliver great hits. But targeting the head was something that people wanted out of the game," Shanahan told ESPN recently, 10 seasons after the Department of Player Safety's debut.

"It was a hard job and it was thankless. As much as we were getting criticized, we tried to always remember that we were going to make the game safer and make it better."

Rule 48 still had that fresh-rule smell in 2011. Shanahan's suspension video was one of the first the department created. It was the first time he used phrases such as "the head is targeted," "principal point of contact" and "prior history of discipline."

It would not be the last.

From 2011-12 through 2020-21, there were 80 suspensions for hits that violated Rule 48 in the preseason, regular season and playoffs. It's the rule on which the Department of Player Safety was built. It's a rule that was created in an effort to reduce the number of concussions in the league, and one that fundamentally changed the way the game was played in the NHL over the past decade.

"What was borderline before that has become clear that it's not acceptable in the game. I think the respect factor has grown," Tampa Bay Lightning captain Steven Stamkos said. "We've seen some of the harsher suspensions put in place. I don't think there's as much of a gray area for players. We know there are punishments."

Here's the story on how the rule came to be, what its impact has been in its first 10 seasons and what comes next.

The impact

George Parros, the current head of the Department of Player Safety, was a winger with the Anaheim Ducks when Rule 48 was introduced. He doesn't remember it affecting the way he played.

"The only thing I remember was the video that Shanahan and [NHLPA executive] Mathieu Schneider put out and we had to watch it in the locker room. It was kind of funny, to be honest. They were both pretty stiff," he said.

Parros has led the department since September 2017. In 2017-18, the NHL had only one suspension for an illegal check to the head in the regular season, the lowest total in seven years.

"I feel we've fine-tuned the game to a great degree," Parros said. "A lot of the hits we see are because the game is so fast. Every once in a while, we see something with some intention behind it, but very rarely."

The number of suspensions has fluctuated since then. It jumped back up to eight regular-season bans in 2018-19, and 12 in total. The biggest season for illegal check to the head suspensions was 2013-14, with 15 in total. The lowest total was four in 2019-20, a season shortened by the COVID pandemic whose playoffs were held inside spectator-free bubbles.

According to Icy Data, which tracks NHL penalties by type, the Ottawa Senators had the most minor penalties for checks to the head from 2010 to '20 with 34, followed by the Boston Bruins (33) and the Lightning (26).

"We watch over a thousand clips a year in our department. About 150 of those would involve head contact," Parros said. "If we suspend five or six times a year for an illegal check to the head ... you can imagine how many were fine, and how many were in that gray area of what we're trying to define here."

Rule 48 has been the basis for several of the NHL's most significant suspensions, including:

• Oct. 10, 2013: Buffalo Sabres winger Patrick Kaleta was suspended 10 games for a hit to the head of Jack Johnson.

• Oct. 3, 2015: San Jose Sharks winger Raffi Torres was suspended 41 games for an illegal check to the head of Jakob Silfverberg.

• Sept. 30, 2018: Washington Capitals forward Tom Wilson was suspended for 20 games, reduced to 14 games on appeal, for an illegal check to the head of Oskar Sundqvist.

Rule 48 has impacted how penalties are enforced, how suspensions are handed out and how players deliver body checks. Shanahan believes it may have even opened up the game offensively.

"When I watch games now, I see players cutting across the high slot and taking shots on goal, and you don't see players zeroing in to hit them," he said. "It's not necessarily about the rule. It's because the players wanted that hit out of the game."

But Stamkos disagreed that enforcement of illegal hits to the head led to braver players in the slot.

"I don't think that it's affected guys taking ice in the middle," he said. "You never think about a guy elbowing you in the head. It just happens."

There was a time when that would happen with no recourse from the NHL. For decades, hits that targeted the head would end up on VHS highlight tapes rather than in a hearing room. A ban on hits to the head seemed like an improbable suggestion.

"There were probably many reasons for that," Parros said. "But there are two that I consider most significant: First, our awareness and understanding of the effects of concussions was really accelerating at that time -- similar to other sports' -- to such an extent that it adjusted the thinking about such hits in a game, in which the puck-carrier normally is bent forward, somewhat leading with his head.

"Second, any such ban would have been a major change, since all of the people in the NHL at that point had been raised and taught how to hit a certain way. They'd be required to change on a dime, into thinking that what they were doing for 25 years is now illegal."

Despite those challenges, a movement to ban checks to the head picked up momentum at the end of 2009.

As one NHL source put it: "The David Booth one was so, so horrifying that it really stopped everyone in their tracks."

The David Booth hit

There are two hits from the 2009-10 season that paved the way to Rule 48. In both cases, the hockey world wanted massive suspensions that the NHL felt its rulebook didn't support.

The first was delivered on Oct. 24, 2009. The Philadelphia Flyers were hosting the Florida Panthers. David Booth, the Panthers' leading goal scorer in the previous season, was carrying a puck through the Flyers' offensive zone. Mike Richards of the Flyers cut across on a backcheck and delivered a hit to Booth's head. The Panthers forward fell, banging his head on the ice before falling limp. A stretcher was quickly wheeled out onto the rink.

Booth doesn't remember the hit, nor does he remember his time in the hospital. The recollection seared into his memory is that of waking up in the ambulance that took him from the arena and feeling an overwhelming rush of panic. He didn't know where he was. His legs and chest were strapped down. He grabbed his team trainer by the collar of his shirt, screaming to get him out of there.

"It was like I was possessed. I was trying to break the seat belts," Booth told ESPN recently.

He has seen the hit since then, more than a few times. People will cue it up on their phones, play it for him and ask, macabrely, "This you?"

Richards was given a five-minute major for interference and a game misconduct by the on-ice officials. Booth was released from the hospital after one day. The Philadelphia Inquirer reported that he "suffered a concussion but no other serious injuries."

Booth would play six more seasons in the NHL and nine more professionally. But he was never the same after the hit, by his own admission. There were cognitive issues. There was also a nagging hesitancy in his game that never really left due to the devastating nature of the hit.

"It's human nature to feel like the victim. That something happened that I didn't deserve to have happen. I think that's the easy way out, to say it's Mike's fault or the league's fault," Booth said. "That's something I want to stay away from. It happened, and it's unfortunate and it changed the course of my career."

The incident also changed the conversation in the NHL. There was outrage from the hockey world, seeking supplemental disciplinary justice against Richards. But the hockey operations department, under Colin Campbell, determined that the hit wasn't punishable under the current rules. For the first time, there was real momentum for a rule change at the November 2009 NHL general managers meetings, which took place soon after the Richards hit.

There had been some conversation about a crackdown on checks to the head through the years. But in many cases, there was nothing on the books that outlawed head contact, so the hits went without supplemental discipline. There were also general managers who would support more penalties for hits to the head. Jim Rutherford, the longtime GM for the Carolina Hurricanes and Pittsburgh Penguins, was an advocate for a total ban on head contact.

What had fundamentally changed about the game, as was evident from the Richards hit, was that defensive players were backchecking harder than they ever had before.

"Back pressure? You never heard of that before," recalled Ray Shero, who was general manager of the Penguins when the head-shot conversations started. "It was obviously becoming a part of the game, and there wasn't a lot of time and space [to avoid hits]."

Shero was an advocate for making checks to an opponent's head illegal.

"I never liked those sorts of hits. It's part not of the game," he said.

Ironically, Rule 48 might not have happened without one of his players delivering that sort of hit.

The Marc Savard hit

On March 7, 2010, the Boston Bruins were visiting the Penguins in Pittsburgh. In the third period, Boston center Marc Savard collected a pass high in the Penguins zone and fired a quick shot toward the Pittsburgh net. With Savard in a vulnerable position after releasing the puck, Penguins winger Matt Cooke skated by and used his left arm to drill Savard in the head. The Bruins forward twisted to the ice, eerily near the location on the ice where Booth was injured months earlier in Philadelphia. Cooke wasn't penalized on the play.

Another hit to the head. Another player stretchered off the ice. Another controversy right before the general managers met again.

"Maybe it's a good thing that the GM meetings are when they are," Cooke's teammate, Penguins captain Sidney Crosby, said in the aftermath of the hit. "There's obviously some confusion as to what's a good hit and what's not a good hit. That's got to be fixed pretty quickly. We've seen it time and time again, and we all debate whether it was a good or a bad hit."

Shero's plan was to fly to the GM meetings after the Penguins game. Bruins GM Peter Chiarelli was sharing a flight with him to Florida for the conference.

"That was a long ride to the Pittsburgh airport. I think it was 15 minutes before we said anything to each other," Shero said.

The next morning, there was a long discussion among the GMs about the Cooke hit and whether there was a remedy for it through supplemental discipline. There was a clamor for Cooke to be suspended, from fans, media and players alike.

"The media was talking, and we were talking internally," said Edmonton Oilers GM Ken Holland, who was then the general manager of the Detroit Red Wings. "You could make the case that it was legal. But all the managers went to that meeting knowing that, because of that hit, we had to make some adjustments to the way the game was being officiated. To make a safer environment, and to protect our players."

The debate was intense. Lou Lamoriello, then GM of the New Jersey Devils, said that suspending Cooke would be akin to "making something up" because there was no rule covering that hit.

"It was like 'The Untouchables' and Al Capone. What, were they going to get Matt Cooke on tax evasion?" recalled Shero, now an advisor to the Minnesota Wild. "There was nothing in the rulebook. There was nothing to have a hearing on."

By not taking action against Cooke, Campbell forced action from the general managers to finally, and formally, create a rule that could cover hits like those that injured Booth and Savard. Several people involved in those meetings agreed that if Campbell suspended Cooke -- which would have been thoroughly popular at the time -- it would have been years before a rule that actually covered the incident would have been enacted.

"There is no Rule 48 if he just does what a lot of the people in hockey and media wanted done at the time, which was to just suspend him despite the rulebook," Shanahan said. "If he suspends Matt Cooke for that hit, then it's quieter. It goes away. You don't have this moment where the managers are wondering what they want to do to make the game better."

What the GMs decided to do was implement a rare in-season rule change. "Beginning with tonight's games, the NHL will implement a new rule prohibiting a lateral back pressure or blindside hit to an opponent where the head is targeted and/or the principal point of contact," the league announced on March 25, 2010.

The announcement also stated that the hockey operations department was empowered to review any such hit for the purpose of supplemental discipline -- a decision that was popular with the players at the time, in the aftermath of hits like the one delivered to Booth.

Shanahan replaced Campbell as the head of player safety on June 1, 2011. But before that, he helped refine Rule 48.

The tweaking

Rule 48 formally appeared in the NHL rulebook for the 2010-11 season. Illegal checks to the head were now defined: "A lateral or blindside hit to an opponent where the head is targeted and/or the principal point of contact is not permitted."

The biggest news in the rule's first iteration was that checks to the head would be subject to a five-minute major penalty and automatic game misconduct, with possible supplemental discipline from the league.

NHL commissioner Gary Bettman called the rule change "a fundamental shift" for the league, but cautioned not to have it apply to all situations.

"There are nuanced differences between acts that some people think are similar, but they're not the same. So you can't be too willing or too quick to paint what happens on the ice that requires supplemental discipline with too broad a brush," he said.

The first season of the rule saw six players get suspended specifically for hits to the head: Shane Doan (three games), Joe Thornton (two games), Matt Martin (two games), Tom Kostopoulos (six games), Mike Brown (three games) and Daniel Paille (four games). There were also a handful of fines. The rest of the suspensions involving head contact were categorized as being for elbowing, cross-checking, charging or the lateness of a hit.

The league quickly discovered that referees who had asked for Rule 48 to be implemented were hesitant to enforce it.

"The referees at the time were saying that on the ice in real time it was a difficult call to make. That they would catch more of them if it was a minor penalty, that with a major, because it was a new rule, it was too punitive. They felt the harsher penalty could be through supplemental discipline," Shanahan said.

In March 2011, Shanahan joined a "blue ribbon panel" of former players turned executives -- Rob Blake, Steve Yzerman and Joe Nieuwendyk -- to tweak the supplemental discipline process and find ways to broaden Rule 48 to cover other hits to the head.

"The real difficult part at the time was figuring out what was just going to be incidental head contact and what was going to be illegal head contact," Shanahan said. "It sounds like an easy thing to do. But it was more complicated than that, and we saw that with the tweaks to the rule over the next couple of years."

In 2011-12, a reworked Rule 48 was introduced. The words "lateral" and "blindside" were removed to widen the application of the rule. The rule stated that the head had to be targeted and the principal point of contact, rather than "and/or." There was also added language about whether the player taking the hit had put himself in a vulnerable position "immediately prior to or simultaneously with the hit" or if head contact "on an otherwise legal body check" was unavoidable.

"The 'lateral' and the 'blindside' was not to say that it was OK to hit a guy in the head like that, it's to say we're not going to distinguish how a player was hit in the head. It could be any position or any angle," Shanahan said.

An illegal check to the head was now either a minor penalty or a match penalty, not a major penalty, to make it easier on the officials.

In the first season for both the NHL Department of Player Safety and the revamped Rule 48, the league issued 13 suspensions for illegal checks to the head for a total of 43 games. The 12 games given to James Wisniewski were the most handed out. It was a rule that saw both repeat offenders and star players get suspended.

The rule's effectiveness was called into question in 2013. Dr. Michael Cusimano, a neurosurgeon from Toronto's St. Michael's Hospital, co-authored a study that claimed Rule 48 didn't significantly lower concussion rates in the NHL. The study was later used as evidence in a class-action lawsuit brought against the league by a group of former players who claimed the NHL was negligent in its prevention of concussions. The suit was settled in 2018; as part of the settlement, the NHL did not acknowledge any liability for any of the plaintiffs' claims.

"Part of it's the way the rule's written. Part of it's the way the rule is enforced. Part of it's the penalties associated with the rule. And part of it is that concussions are also coming from other causes like fighting, that is still allowed," Cusimano told the Canadian Press in 2013.

The rule continued to be rewritten. For 2013-14, the players requested that "principal point of contact" be changed to "main point of contact" in the rule. The word "targeted" was dropped in favor of "avoidable head contact," leaving intent out of the mandatory criteria.

"Any time there was something in our language that confused the managers or the players, we would tweak it," Shanahan said. "To remove 'targeting' was meant to suggest that a hit may not have been intentional, but it could be reckless. That a player with no history could have thrown a reckless hit."

Damian Echevarrieta, vice president of NHL player safety, laughed when recalling this change. "I love Shanny, but he would say things like 'unintentionally targeted' and I'd have to tell him that the word 'target' has intention in it. You can't unintentionally target something!" he said.

By 2016, Rule 48 looked much like it does today, emphasizing the illegality of reckless or avoidable hits to the head, while mentioning the nuance of an opponent's body position when the hit was delivered. The rule makes it clear that if the head is the main point of contact and the contact was avoidable by delivering the hit a different way or not delivering one at all, then it's an illegal check to the head.

Needless to say, there was a learning curve for all these rule tweaks, and for the rule itself.

The re-education

The last decade saw players, coaches and team executives struggle to understand Rule 48 and its application, especially in early hearings. One person with knowledge of the hearings characterized the typical counterarguments from players and teams as "victim blaming," as they spoke more about the opponent taking the hit than the hit itself.

"The first couple of years were very difficult," Shanahan said. "Players and managers would come into the hearings and say, 'This is a legal hit.' You have to acknowledge that six months ago, it was. But it's not anymore. That was a huge shift."

The videos that the department created helped with the education, although not necessarily for the experienced players in the NHL.

"The videos weren't for the players in the league at that time. They didn't even watch them. We were making them for kids that were playing," Shanahan said.

One of the biggest factors in the player education process was the rookie orientation camps that were started within the past decade. In between sessions with top prospects in which they learn about social media etiquette and receive financial advice, the Department of Player Safety gets them for an hour, and explains the nuances of things like Rule 48. Shanahan hopes they're already familiar with it.

"The next generation is only about four or five years down the road. These kids that were between 14 and 16 would be impacted by these videos, for when they reached the NHL," Shanahan said.

The question remains what Rule 48 will look like for those next generations.

The future

Chris Nowinski is co-founder and CEO of the Concussion Legacy Foundation, a nonprofit organization leading the fight against concussions and CTE. He's been an open critic of the way the NHL has handled both. But he said Rule 48 was a net positive development for the league.

"We all know that player behavior can be changed and penalties are a great way to do it. Rule 48 and the education videos that were released were very effective in making the game safer for those catastrophic hits to the head."

Nowinski feels the NHL still isn't candid enough with its players about the long-term impact of concussions in contact sports. "The responsible thing is to educate players about what they're getting into," he said.

Nowinski saw Rule 48 as an obvious evolution for the NHL, and ultimately good for business.

"The hits to the head 10 years ago were highlight videos. Or they were called out and made the league look bad. So it's a very clear PR strategy to get them out of the game," he said. "It's about optics but it's also about protecting your stars and keeping them in the game."

He wonders if the next evolution will be a total ban on any contact with the head.

"They're not selling tickets based on hits to the head," said Nowinski. "Rule 48 proved you can change that behavior. Eliminating hits to the head could [make the NHL] more popular. It could be less popular. It's a shame no one wants to try."

There's always been a sense that a total ban on head contact would change the way the game is played too dramatically. But there's a notion that Rule 48 could go further, if not that far.

"I think there's a possibility that more hits become illegal than are currently considered illegal hits," said one NHL source.

Holland said there hasn't been much discussion about a total ban on head contact among the GMs recently.

"I think it's cooled down because of the effectiveness of Rule 48. But at the end of the day, it's going to be hard to have any rule like that in there. The game is played at such a high speed. There's physicality. You're always going to have some head injuries," he said. "With the education of the players and the rule changes, I do think we're in a good place right now. But three years from now if there's too many people injured, we might have to reassess. I can't tell you what the future is going to bring."

While a total ban on head contact may not be imminent, Parros does see one aspect of checking that could fall under the Rule 48 umbrella: hits where the head violently collides with the boards.

"We are constantly looking at and analyzing our game, how it's played and where it can be improved or regulated in the best possible manner. When Rule 48 was first implemented, we were trying to eliminate those open-ice hits that 'picked' or 'targeted' the head. Over time, I think our efforts have worked quite well in this regard," he said. "Looking forward, with many of the hits that we see, head contact occurs in and along the boards, and less so in the open ice. Secondary contact with the glass and boards is something that we see more of and will continue to monitor."

Whatever the next iteration of Rule 48 looks like, it's clear that one decade in, the league is safer, with the rule eliminating many of the catastrophic hits that were previously a commonplace part of the game.

If it existed in 2009, would players like David Booth have had a different career?

"It's a hard question to answer. You never know what could have happened. How many times we've been saved from something and not realize it," Booth said. "But there's no doubt that it had a beneficial impact. Some of those hits that used to happen ... they were crazy."