The 2016-17 BU PP: Passes (and shots) vs. the PK

Previous posts:

Intro and general shot locations
Individual shot locations
Shot outcomes
Passes and shot assists

So many thank yous to Ryan Stimson for all his help with providing me resources to make this project the best it can be, and another thank you for some specific help on this post in giving second opinions and helping ID penalty kills and forechecks when they weren’t super clear!

In the last post, we looked at individual pass maps for players as well as their /60 pass rates. Now, I’d like to zoom out a bit and try to visualize team and unit tendencies, specifically whether these tendencies changed based on what penalty kill the Terriers are facing. Or maybe not “change” necessarily, but I’d at least like to see whether they’re at the whim of the PK or if they just carry on about their business regardless of who/what they’re up against.

Let’s start off by establishing which teams BU faced and what penalty kill they ran in those games. I’m going to explain each penalty kill and provide an illustration for each so we’re all on the same page. I’ll map out both defensive zone formation as well as neutral zone forecheck, but the latter won’t be discussed at length until my next post when I talk about breakouts and entries.

BU played each team once except for Maine who they played twice in a home and home series one weekend. The PP1 and PP2 columns just indicate whether that unit faced the particular opponent. Against Yale, BU was using a different PP2 (Bobo Carpenter, Patrick Curry, Ryan Cloonan, Brandon Hickey, and Chad Krys) even though that game was the first iteration of this PP1. For the UML game, there was only one personnel swap for PP2 (Nick Roberto in for Kieffer Bellows), but the coaching staff switched up the formation as well to an Umbrella PP with Curry and Roberto in front of the net. And when playing Merrimack, the Warriors used a Wedge+1 against PP1 and a simple Box against PP2. I’m trying to look at two very specific power plays in this project, so I omitted tracking the events that took place with those PP2s out on the ice. Reminder that PP1 is usually a 1-3-1 power play while PP2 is a split power play.

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It’s pretty convenient for me that apparently at least half of Hockey East uses a 1-3 NZ forecheck on the penalty kill. I’m going to wait til next post to get into forechecks, though, just because as I’m writing this I’m realizing how long it’s going to be just with penalty kill formations. So first, numbers!

These are two tables that just note the number of shots (top) and passes (bottom) the team as a whole and each unit recorded against each opponent. Again, again, again we are extrapolating a lot, especially when it comes to breaking these rates down further and further. In that sense, I wouldn’t necessarily take the rates themselves as gospel, but instead use them as kind of a guide to what’s going on.

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For example, at the rate the Terriers were passing against UMass Amherst, which ran a Wedge+1 penalty kill (see below for explanation), it appears that PP2 was moving the puck around more. They have a higher passes/60 than PP1. If we think about that in context, a Wedge+1 has one penalty killer running around chasing the puck, and since PP2 is more spread out and has four people at the points and on the boards compared to PP1 which has three in those spots, that +1 is chasing more people over a greater distance, so if the puck is being moved faster, he won’t be as effective as a different kind of penalty kill might be.

Here’s a look at the tables just organized by penalty kill, not opponent. Basically everything is the same as the top two tables except Merrimack (vs. PP1) and UMass have been combined into just the ‘Wedge+1’ row and Merrimack (vs. PP2) gets its own Box row. After combining them, we can see that shot rates between the two power play units do not differ significantly against a Wedge+1 PK, but PP2 is still passing much more when facing a Wedge+1. And like I said last post, that doesn’t necessarily mean they’re better or worse. It just means they’re different power plays and they’re moving the puck around more than PP1.

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Box/Large Box

The Box is typically a passive penalty kill formation that aims to keep passes and shots to the outside. Players will move toward the puck carrier to try and pressure but just from a distance. They won’t go too far out and so are not aggressively on top of the puck. In a Large Box, though, players will be more aggressive and try to attack the puck carrier to force turnovers or quick decisions. However, this can take some penalty killers out of position and open up the middle, which the Box, as a PK, tries to keep the power play out of.

Yale used a Large Box penalty kill against BU, though as I mentioned before only the first unit faced it. It looks something like this to begin and then as the puck is moved around, it shifts toward one side of the ice or another and players (usually the forwards) will go out to the boards and points to pressure. The defensemen will also pressure, but from what I’ve seen they’re not quite as aggressive.


To see how BU fared against this penalty kill, I’ve put together a shot chart, a pass map, a failed pass map, and two heat maps: one that shows where passes started and one that shows where passes ended up. I wasn’t sure how to put them together without making it a bit overwhelming to look at. Click the images to see a larger version of them. If you see passes on the PP1 map made by a PP2 player or vice versa throughout, it’s because the majority of personnel on the ice were of that unit, even if the player isn’t a regular there.


Failed passes are passes that either didn’t make it to their intended target for a number of reasons, or they left the zone entirely (while possibly missing their intended target). I think the legend is self-explanatory, but RIM means a pass that was rimmed around the boards like before, BLOCKED means the pass was blocked by a penalty killer, and INT means the pass was intercepted with control by a penalty killer. Another one you’ll see later is BAD which just means it was a bad pass that wasn’t able to be corralled or kept by the receiver.

So the Terriers actually got two shot attempts off in the slot despite this being a Box-based PK. However, the goal was off the rush so they weren’t really in formation yet.

The density plots/heatmaps whatever you want to call them below are just to illustrate the above pass map in a different way. I thought this might make it easier to see the shape of BU’s passes through a density plot instead of just having you guys try and figure out the densities with just your eyes.

It looks like all but two of BU’s passes originated from outside the home plate area, and only one of those was actually in the slot, so Yale did a pretty good job at keeping a lot of the action on the outside. For where the passes ended, again, most of them ended up on the perimeter of the attacking zone or at the very bottom of that home plate area. And if you check back up at the pass map itself, only two passes actually went through the slot and one that tried to was blocked.

Now I’m going a little out of order, but Merrimack used a simple Box PK against PP2 when facing them. This allowed them to just pass the puck around the outside a bunch and kept them mostly out of the middle of the ice.


So just to reiterate, look at how empty the middle of the ice is. Merrimack wasn’t using a Large Box, so they were not applying heavy pressure, just kind of shifting their tight box toward the puck when it was moved. This allowed PP2 to operate how they wanted, but didn’t necessarily give up anything dangerous as nothing crossed the slot and just one shot came from inside the home plate area.


Now the Controlled penalty kill is similar-ish to the Box penalty kill in the sense that it sometimes uses the Box formation. Specifically, the Controlled PK stays in a Diamond formation when the puck is up high (ex. at the points) and pressures the point and then shifts to a Box when the puck is low (ex. below the goal line) and maintains a Box-like pressure.

Boston College faced the Terriers with a Controlled penalty kill, and this is how BU did against it!

A handful of those Patrick Harper/Clayton Keller passes on the right side there make up a lot of PP1’s passes against BC, and that’s due in part to that Diamond pressure. When Keller had the puck, usually the player on top of that diamond would come closer to attack the puck and force Keller to make a decision, and when he’d move it to Harper, the right-side penalty killer would then come out to pressure him. And here too we see some behind the net passes that we didn’t see against Yale above.

For PP2, if we look at the tables from before, we can see that they were passing at a pretty high rate for the length of time they were on the ice, but all these passes were super high and only two even originated/were received below the faceoff dots. They were only on the ice for 1:09 against this penalty kill and their PP is set up in such a way that everyone except Patrick Curry is positioned higher than the dots, so that’s probably most of it, but I don’t know how many valuable chances you’re going to get keeping the puck that high. I don’t really love the split power play, so some of this might just be my bias against it!

Credit to BC for keeping the slot almost completely clean for passes and shots, only allowing one successful pass and shot attempt. If you look below at the failed passes chart, you’ll see that the Eagles thwarted two pass attempts that made their way into/through the slot. PP2 completed all their passes, which is why there’s no failed pass chart for them.

And here’s a look at the pass densities!


A 1-1-2 PK is initially set up similarly to a Wedge+1 (see explanation below), but instead of just sending one guy out to chase the puck, the 1-1-2 has two penalty killers move to pressure the carrier and two stay in the slot in kind of a vertical line. I added that second illustration to show, for example, what happens when the puck is up near the corner and how the penalty kill moves.

So Maine used this penalty kill in both games and against both units while playing BU. The first unit has a really full pass map as you can see, with a lot of concentration in that Harper/Keller area again. PP2 again kept most of their passes up high, but did manage to get some passes a bit lower this time. They even got a clean pass across the slot there.

The samples with more data are more fun also because you can see shapes in the shots! PP1 has way more presence in the slot compared to PP2 which, as usual, sticks to its perimeter shape with a couple shots from in close by Curry.

I really like these PP1 density plots because I think they give a nice view of the shape, which again is due to a larger sample size. PP2 you can see just how much goes through Dante Fabbro and Chad Krys.


A Wedge+1 power play is basically what it sounds like. There’s a wedge (triangle) of three players that guard the low slot/slot and front of the net while the one remaining player goes out and pressures the puck. Depending on where the puck is, players can rotate in and out of the triangle so someone closer to the action is pressuring.

Merrimack used this power play against PP1 and UMass Amherst used it against both units. Like the 1-1-2 pass maps, there was a fair amount of ice time available to track for this PK, so things are a bit more fleshed out.


Lots of good pass movement for the power play against this penalty kill. One thing I’m noticing is that there doesn’t seem to be a ton of change in the way the power play operates based on penalty kill. The general locations are largely the same. PP2 is going to run through the defensemen no matter what, and PP1 operates often in that high triangle, but doesn’t have too much trouble getting down low.

More than against other penalty kills, BU sent the puck out of the zone on its own six times (three for each unit). Other than that, PP2 only failed behind the net and PP1 had a few around the slot interrupted and a few off to the sides.

In terms of shots, PP1 had a bit less slot presence than against the 1-1-2. This could have to do with the tight triangle guarding the slot, but BU still got plenty of chances right in front of the net.

Where there was a stark absence of pass starts in the middle of the ice for the 1-1-2, there are a few passes that PP1 makes more toward the middle, and the reception areas are similar. For PP2, that concentration remains at the points, but there’s definitely some more going on lower down.


The only way I really know how to describe this penalty kill is to show it in a play that actually happened, so here it is below. It’s a very aggressive penalty kill that UMass Lowell used that overwhelms the puck carrier by sending three people out toward the puck at a time while one holds down the fort in front of the net. In the play below, two penalty killers are on Jakob Forsbacka Karlsson trying to retrieve the puck below the goal line while a third tries to take away the pass option to Keller behind him. JFK doesn’t have control of the puck in this situation and Lowell ends up gaining possession. I’ll post a quick gif of it under the illustration so you can see it in action.



This is typically how the PK looks. If the puck is along the boards, those two penalty killers will create that 2-on-1 (or 2-on-2 if another PP member comes in) while a third eliminates a pass. When the puck is high or just being rotated at the points, it looks similar to a Box or Diamond that shifts based on the play and has players move out to pressure.

This penalty kill was incredibly successful against the Terriers, giving up just six successful passes to PP1 in 2:40 of play (small sample I know but still!). They were the second best penalty kill in Hockey East that year (only BU was better) and ranked ninth in the country.

I want to take a closer look at this penalty kill in the next post when I look at entries because a large part of this was preventing the Terriers from comfortably setting up. If things aren’t settled or in control, the PK swarms over to try and force a turnover and subsequent clear. As a preview, in seven entry attempts against Lowell, BU only got set up twice. They entered with control in three of those attempts and didn’t get set up in any of them. It’s impressive!

But because it worked so well against the Terriers, these charts aren’t super fun or telling. It just shows how well this penalty kill did really. There’s not a whole lot to absorb here!


One thing I will say is that PP1 only had three failed passes, which seems to imply Lowell wasn’t even really letting them attempt to pass it. This is why I want to look more at this, so I can show exactly why this was happening.

That’s all for this one. Thank you for sticking with me if you got to the end here. I had no idea this would end up being this long! For my next post (and I think last of this project), I’m gonna look at breakouts and entries. That should be up within the next week!

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