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Forechecking Matchup Analysis: Bruins vs. Leafs

Searching through data to find trends in the Bruins forecheck vs. the Leafs breakouts

NHL: Boston Bruins at Toronto Maple Leafs John E. Sokolowski-USA TODAY Sports

Introduction

In the last article, we briefly discussed breakouts and forechecks. For this particular article, we are going to add some additional rules to filter out the noisy events that may fall into these categories. The events we are looking for have:

  • The puck residing below the faceoff dots to start the breakout sequence
  • At least one forechecker below the faceoff dots
  • The player trying to break out the puck must make an obvious hockey play (ex. skate, clear, pass)
  • The forecheck must be actively trying to get the puck back (not making a change)

So the following play won’t be included because the puck resides above the faceoff dots when Tavares turns over the puck to Marchand.

Tavares can’t control the puck on his backhand and Marchand recovers

This is a controlled exit and is valuable, but we want to key in on more systematic breakouts today. For each event recorded, the following details are grabbed:

  • Who and where the breakout occurred.
  • Whether or not the breakout led to a controlled, uncontrolled, or failed exit
  • All of the passes in the sequence and who made the passes to whom
  • What type of breakout it was (Up, Over, Wheel, Reverse, Clear, Rim, Controlled, Goalie, Misc.)
  • How many forecheckers were below the faceoff dots
  • The cause for the breakout (ex. Entry, Rebound, Turnover)
  • The forechecking forwards

With all of that in mind, let’s look at the Bruins forecheck versus the Leafs breakouts.


Searching for Trends

In order to draw out potential strengths and weaknesses as it pertains to the Bruins forecheck against the Maple Leafs, we must first look at the data. There are two reasons we do this first. For one, the data is more or less objective. It tells us what happened. Our eye test tells us why they happen. We need to know what before why. Additionally, humans are susceptible to anchoring bias. We stick to the first piece of information we obtain, so we want the first piece of information to be the best.

Above is a simple plot of the exit locations for the Maple Leafs. As you can see, the Bruins do a terrific job of keeping the Maple Leafs on the perimeter. This is important because hockey is a battle of space. The boards help the forechecking team take away space from the puck carrier which creates pressure. Pressure is what forces turnovers and uncontrolled exits.

Adding another element to the first graph, I was interested in also looking into passes leading up to exits, and the ice covered between the last pass and the exit. The dots are the final pass reception in the exit attempt (this could also be the exit location) and the lines display the ice the skater covers between receiving the pass and exiting (or failing to) the zone. The same trend exists. Very few passes are completed in the center lane. Furthermore, the Leafs skaters move away from the center lane as opposed to moving towards center ice. This suggests that the Bruins forecheck is controlling the battle.

We will build on this more in a second, but let’s first address the systems that Boston plays. The Bruins generally use a 2-1-2 or 2-3 forecheck. These two forechecks are generally the same, the only differences being the depth of the F3 (high forward) and the width of the defensemen. Coaches may also make minor changes based on their philosophies and matchups. Below is a short, but thorough explanation of the 2-1-2 forecheck if you are unfamiliar.

We can further be certain that the Bruins do this because they deployed at least two players below the faceoff dots 71% of the time on forechecks from entries against the Leafs this season.

Above is the first part of a forecheck on January 12th. Jakob Forsbacka Karlsson is the first forward in. He ties up the puck carrier which prevents a quick up-and-out. Next, Danton Heinen comes in to help. It might be unclear, but the puck pops loose. Nikita Zaitsev goes to clear the puck away, but Heinen prevents that. Ryan Donato is the F3 and is reading the play. Initially, he is eyeing the possible chip up the boards. Once that option is taken away, he is reading the play in order to know where to go next.

Zaitsev can’t connect with Gardiner, so the puck heads up the wall. Donato must pressure the puck. Forsbacka Karlsson is taking away the weakside stretch pass while Heinen is looking to defend a chip up the wall. Lindholm drops the puck back to Gardiner who panics at the second wave of pressure, sending the puck out of the zone and onto a Bruins’ stick.

In the play above, the Leafs never control the puck above the faceoff dots, nor more than a few feet away from the boards. This is a giant success for the Bruins.

Here is yet another example of a successful 2-1-2 forecheck. The first two forecheckers slow down the play and engage in a puck battle. When Toronto wins the puck up the boards, the F3 is there as a second layer, forcing a turnover and creating a shot. Moreover, the same trend continues. The Maple Leafs failed to control the puck above the faceoff dots nor a substantial distance from the boards.

When the Bruins don’t use a 2-1-2, they will deploy an aggressive 1-2-2 that may end up looking like a 2-1-2.

“Structure follows strategy,” is a quote from a marketing textbook I read this semester. I immediately stuck it on my bulletin board by my desk. While the Bruins deploy a 1-2-2 in this situation, presumably because they are up by four goals, the strategy stays the same. The first two forwards in prevent the quick play up the boards. When the puck gets moved to the weakside, the third forward activates. At the end of the clip, we have a structure that resembles a 2-1-2.

At this point we can hypothesize that the Bruins’ forechecking aggressiveness keeps the Maple Leafs on the perimeter on their breakouts, but is there evidence that being more aggressive is beneficial for the Bruins?

Before we get to that answer, let’s address some previous research on the topic. Ryan Stimson was able to research the topic a couple of years back and found that an aggressive forecheck is best. The sample size was also small and should be taken with a grain of salt, but this also supports our hypothesis.

When the Bruins only deployed one forechecker below the faceoff dots (29% of the time), the Leafs only controlled 12.5% of their exits. Further more, as we covered last article, we can weigh exits by the chance that they will result in an entry. The Leafs weighted successful exit percentage is 20.5% in this context. Below is a visualization of this. Note that the solid lines are the last completed passes, dotted lines are skating paths to the exit, and the dots are where the the event occurred.

The Bruins are able to keep the play to the outside just as well, if not better. Here is the same graph for two or more forecheckers below the faceoff dots.

While the Leafs still can’t penetrate the center lane, it appears that the Leafs have more success here. When the Bruins deploy two or more forecheckers below the faceoff dots, the Leafs control 22.0% of their exits and their weighted successful exit percentage also rises to 26.8%.

Is there merit in changing to a more conservative strategy for the playoff series against the Leafs? Find out in the next article.


Summary

The Bruins have deployed an aggressive forecheck in their games against the Maple Leafs this season. Their forecheck is successful, keeping the Leafs low in their zone and close to the boards. The 29% of the time the Bruins only send one forechecker below the faceoff dots, the Bruins forecheck is even more successful.