Coaches often talk about complementary abilities when they feel like explaining the structure of their lines. Generally, it's a combination of a shooter, a playmaker, and someone with the tenacity to gain the puck along the boards.

This model is used a lot around the league, and even with Artturi Lehkonen replacing Brendan Gallagher as first-line right-winger in the Montreal Canadiens’ last game, the top trio of the Habs still fits that model relatively well.

Other trios become efficient due to a focused ability to do one specific thing. Usually that's putting pressure on the opponent. Historically, this has been the role of every fourth line across the NHL, although it has started to change dramatically in the past few years.

A strong forecheck able to create multiple turnovers can be as efficient at creating offence as skill on any given night. The line comprised of Charles Hudon, Tomas Plekanec, and Lehkonen had done exactly that in their games together, starting with their first pre-season match, and ending when they were separated in the game against the Chicago Blackhawks in order to help spark the rest of the forwards.

This new variety of energy player is not a traditional grinder and he doesn't lack talent. Hudon and Lehkonen both have great shots that should have netted them a few goals this season, and Plekanec was once able to put up a good number of points. However, their ability to anticipate the play and work together were the main factors responsible for their strong performance on the ice.

While a chip-in to gain the offensive zone doesn’t generally transform into scoring chances as much as a controlled entry, that forward line would still get more shots from high-danger areas than other Habs forwards using that strategy.

Hudon-Plek-Lehk bright spot for the #Habs. Non-stop forecheck, locking the puck in the o-zone. Only line able to involve D-men on offence. pic.twitter.com/LNsfjTO6Gq — David St-Louis (@RinksideView) October 10, 2017

This shift was one of the best from that line in the past week, and it happened with less than 10 minutes left and down five goals versus the Washington Capitals. This level of intensity in a lost cause speaks volumes to why those three work so well together on the ice. They went on to have a couple of other showings similar to this one before the end of the game.

Their success usually started with their forecheck. One forward would dump the puck at the blue line — either because he couldn't go any further as he encountered the defensive wall of the other team, or because he received a pass in the neutral zone while having very little speed — and outrace the defender to the end boards to get it back.

Usually that manoeuvre is anticipated and an opposing defenceman is ready to go fetch the puck. The method can work if the forward who dumped the puck in, or a teammate who is already in motion, goes in and puts pressure on the defenceman playing that role.

Usually the dump-and-chase method is a fruitless exercise, and one that served as a constant source of criticism for Michel Therrien’s offensive strategy. The trick is to force the retrieving defenceman into a single option when he reaches the puck by placing pressure on either side of his body. That means you either skate along the boards, cutting the possibility that he could send the puck back to his forwards, or you go directly towards him cutting his option to rim the puck around or skate behind the net.

Either way, if executed well (and by the right type of player), you can anticipate where the puck will be sent on an attempted breakout pass. Then it's on your forechecking partners to support the pressure on the puck-carrier by positioning themselves to intercept the puck. This always has a certain element of risk as they have to judge if they'll be able to pinch up in time while often starting from high in the offensive zone.

Plekanec's line had been very effective at getting to the puck-carrier quickly and causing him to rush his next move. This allowed them to jump on poorly made passes, or battle with opposing forwards to gain possession. A crisp execution and an unexpected chemistry between the three forwards this early in the season turned those turnovers into some great scoring chances.

The line continuously won board battles in its time together. By having the other team collapse low in the zone trying to get the puck back, they were able to reach their defenceman with passes to the blue line, allowing them a lot more space to support the offence.

Involving all five players is the key to a sustained attack. The fact that the Habs’ blue-liners were set up in this way was another reason for that line’s success. It was especially successful with Victor Mete, who rarely shies away from offensive involvement.

In short, Plekanec's line had a clear identity and real chemistry. They understood that scoring a goal is often a process, and they didn't hesitate to work at it every time they were on the ice. Unfortunately, their dominance didn’t lead to the results they deserved.

Based on recent reports, it's probable that Claude Julien will experiment with other lines for the next game, splitting up his most effective one to help the other struggling Habs forwards. Notably Alex Galchenyuk, Phillip Danault, and Andrew Shaw, who have shown no chemistry together and are in need of a shakeup.

A lot of the things that made Plekanec so effective with Lehkonen and Hudon are also reasons why the Danault line is struggling. They are often not on the same page in the offensive zone, having two players who often look to cycle the puck, and Galchenyuk who constantly tries the high-risk, low-percentage play over establishing possession.

Looking at Danault, he's able to protect the puck well, but doesn't always recognize the space available to him. With the puck, he often waits for an opposing defender to close on him instead of using the separation he has to make a play or drive the net.

It's clear Galchenyuk likes to skate to and remain in the slot to get his shot off. However, if his teammates can't find him in those scoring areas because they can't create enough separation from defencemen to feed him the puck (which is not something either Shaw or Danault are able to do consistently), Galchenyuk will remain mostly ineffective. Gone are the days when Alex Radulov’s tenacity would peel off blue-liners to give Galchenyuk plenty of open space.

Until the talented forward of the Habs shows he can put the extra effort to adapt his style to different players, helping drive a line's offence instead of waiting for it to come to him, it will be hard to convince Julien to try him out with more skilled linemates. Although that might be the way to get him to produce this season.

One thing is for sure: the Habs’ head coach has inherited a complex puzzle.