“Between the two blue lines,” said Bruins coach Bruce Cassidy, “we can’t let that become a major obstacle for us.”

The Senators, however, do not like when opponents consider blue line-to-blue line working conditions to be ample, welcoming, or comfortable. Guy Boucher’s intention is to turn the neutral zone into a sweat shop. The demonstrative first-year Ottawa coach saves his biggest smiles for when opposing rushes melt into puddles in the middle of the rink.

Boucher is a contrarian. For three years, he promoted a one-man forecheck in Tampa Bay. In 2010-11, one more win would have placed the Lightning instead of the Bruins in the Stanley Cup Final. Boucher has since implemented his 1-3-1 system in Ottawa, where he replaced Dave Cameron.


Boucher’s system is more of an outlier now because of the leaguewide movement toward the two-man forecheck. Most teams preach aggression, figuring that a smothering forecheck promotes more potential time with the puck in the offensive zone.

Boucher does not agree. He prefers to scatter his traps in the neutral zone. If his players execute the system correctly, opposing advances go there to die.

“They’re very defensive,” said Bruins winger Brad Marchand. “They don’t give up a whole lot. They always have five guys back and give up very few odd-man rushes. Anything you get, you have to really work for.

“Special teams are going to be huge in this series. We’re really going to have to play down low and work down there. That’s going to be our focus. They play very tight. They don’t give up a lot. We’re going to have to earn everything we get.”

The 1-3-1 is an iteration of the left wing lock, which Detroit used in the 1990s and 2000s. In Boucher’s system, the five skaters have one priority: Stay above the puck.


Sometimes the first forechecker is aggressive. In previous meetings, David Pastrnak and Kevan Miller scraped themselves off the ice after Mark Borowiecki slammed down the left-side boards in pursuit of a rim and dumped them on their backs.

At other times, the first forechecker steers the puck carrier in a preferred direction. But Job 1 for F1 is to serve as a deterrent, even when he’s relatively stationary.

“He’s just standing in the middle,” Miller said. “Last game, maybe when we were swinging a couple guys, he tried to steer us to one side a little bit. But when he’s just standing still like that, there’s not a whole lot he can really do to influence the play. It’s more that he’s trying to stay above the puck. He’s not really trying to get you to go either way.”

Either the left or right wing, depending on the puck’s position, slides back into a three-man barricade in the neutral zone. One defenseman retreats into the defensive zone, tasked to be first on a chipped-in puck.

Miller doesn’t have to think back far to recall how the Senators can blunt neutral-zone approaches. In the first period of the second-to-last regular-season game, Miller tried twice to break the puck out on the right side. Both times, Miller drove the puck into the teeth of Ottawa’s 1-3-1.

On Miller’s first approach, he believed he had beaten Tom Pyatt, Ottawa’s first forechecker. But after Miller passed to Ryan Spooner, Fredrik Claesson, one of the three-wide phalanx alongside Jean-Gabriel Pageau and Mike Hoffman, engaged the center in a puck battle. When Spooner tried to bump the puck to Matt Beleskey, Pyatt and Claesson converged to produce a turnover.


Spooner regained control after Pyatt’s soft dump-in. Spooner wheeled around the net and passed to Miller for his second breakout attempt. It failed once more.

Claesson closed again and gained possession after Miller tried a bank pass off the wall.

Miller eventually won a puck battle below the goal line. By then, Spooner’s line needed a change. More than 30 seconds had ticked by.

Ray Ferraro has gotten a better look at the system than most. As TSN’s analyst for approximately 25 Senators games, Ferraro had a front-row seat between the benches to study their neutral-zone play. The ex-NHLer saw Ottawa clog up the middle, force opponents wide, and chew up teams that didn’t advance the puck rapidly enough.

“You need really quick puck movement,” Ferraro said. “Before they can get snug on you and choke off your ice, you have to move it to the next guy. The D-to-D pass is too slow. They smother that. They just shift across the ice. They don’t really move anywhere. All you do is give them more time to get set.”

If the 1-3-1 discourages the Bruins from moving the puck quickly, there are alternative trap-busting methods. They can execute high flips. They can post up a wing to get a piece of a long-distance pass before it enters the zone. They can play chip-and-chase through center ice. The point is to get the puck behind the 1-3-1 and work the Senators down low where, like most teams, they have soft spots.


Boucher’s system can mask shortcomings. The Senators scored two fewer goals (212) than they allowed (214). The 15 other playoff teams posted positive goal differentials, including the Bruins (plus-22). Ottawa posted a 48.6 percent Corsi For rating, second-lowest among playoff teams. They have three go-to forwards in Hoffman (26-35—61), Kyle Turris (27-28—55), and Mark Stone (22-32—54), but the up-front threats decline after that.

But they have a difference-maker where it counts. Erik Karlsson finished the season banged up, but the electrifying three-zone defenseman (17-54—71, 26:50 of ice time per game) is a one-man offensive juggernaut, blessed with the skill to bombard goalies with booming slap shots, slalom through would-be checkers, and give the Senators regular four-man rushes.

Karlsson does this while being responsible defensively. When he is part of the three-wide formation, he can anticipate when to step up, challenge a puck carrier or pick off a pass, and go on the hunt.

“Carrying the puck through center ice is not a good plan,” Ferraro said. “You’re going to get choked off somewhere. I would almost have it built into my game plan that when Karlsson is on the ice, you’re never turning the puck over in the middle of the ice. Because it’s different when he jumps into the play. The guy is brilliant with the puck.”


The Bruins have solved the 1-3-1 at times. On March 21, their No. 1 line totaled three chances on its first shift. After taking a quick cross-ice pass from Zdeno Chara, Patrice Bergeron hustled through center ice with Marchand driving the middle. Marchand breezed through the trap to backhand a shot on net.

Later in the shift, because of their predatory puck skills on the walls and down low, Bergeron, Marchand, and David Backes got two more good looks on goalie Craig Anderson.

The Bruins moved the puck quickly. But they also relied on Marchand and Bergeron, two of the best straight-line puck carriers in the business.

They usually have another in Torey Krug, who can lug the puck through center ice and pick his way through trouble. But Krug is out for Game 1, and it is unlikely to be the last game he’ll miss.

The Bruins signed Charlie McAvoy because of his puck-pushing prowess. But it is a huge ask to expect a 19-year-old to solve Ottawa’s 1-3-1 while making his NHL debut in the playoffs.

“If he can’t play or has limited effectiveness, that’s a big loss for them,” Ferraro said of Krug. “The one previous game in Boston, Krug got up the ice pretty dangerously a couple times.

“Who else is going to do that? Maybe Colin Miller. But man, that would be pretty erratic once he starts to do that. If they decide to go to McAvoy, for a guy playing in his first playoff game, it would look like things are coming a million miles an hour at him.”

The Bruins would be best served to grab a lead and force Ottawa to loosen its trap. The Senators went 29-6-3 when scoring first in the regular season. When they’re leading, they have no reason to slacken their coverage. They lock it down, brick up the neutral zone, and force opponents to make mistakes.

It can be a tough watch. But Ottawa is interested in wins, not entertainment.

Fluto Shinzawa can be reached at fshinzawa@globe.com. Follow him on Twitter @GlobeFluto.