In 2011, Kansas City cast aside its magical wand, dropping the Wizards moniker and rebranding itself as Sporting Kansas City. The team went on to win the Eastern Conference that same year (and in 2012), lift the U.S. Open Cup a year later (and in 2015), and claim the MLS Cup in 2013. Sporting KC’s change was much more than just a name, though – it was a tactical formation shift that really brought the side success.

The 4-3-3 wasn’t a new formation by any means, but Sporting KC played it well. When head coach Peter Vermes took over toward the end of the 2009 season, his team was one of the worst in the league. But his tactical shift combined the best of attacking and defending together in one strategy, resulting in KC sending in cross after cross in the box, and winning most possession battles, despite consistently being at the bottom of the league for time of possession. Success followed. Other teams in the MLS took notice and started trying to imitate what KC had created by attacking with quick wingers and applying consistent pressure on their opponents.

Before Kansas City’s big change, MLS seemed wedded to the 4-4-2. And for good reason – the 4-4-2 is a solid formation, with four defenders, four midfielders, and two forwards. It’s easy to teach, easy to run, and can be dangerous if you have a couple forwards with great chemistry up top, and wide midfielders who can get forward to support the attack.

In fact, the 4-4-2 is one of the best-known formations in soccer, rising to popularity in the 1980s when Arrigo Sacchi took over AC Milan and proceeded to win back-to-back European Cups, a rare feat. Under Sacchi, Milan played a high defensive line, keeping the play in the middle of the field and making sure the distance between the backline and the forwards was rarely more than 25 yards. This reduced the gaps that are a central weakness of the 4-4-2, and created a situation where the opposition needed to burst quickly through three lines of players, which most were unable to do. Sir Alex Ferguson and Manchester United also dominated with the formation for 20+ years, though Ferguson has been known to say that he “had never played a 4-4-2” – his version was more of a 4-4-1-1 with split forwards.

Right around the time MLS began embracing the 4-4-2, Europe started moving away from it. The change toward a 4-2-3-1 (often a modification of the 4-3-3) began in Spain, but the rest of Europe took notice when a 4-2-3-1 Real Madrid side knocked out reigning champs Manchester United in the quarterfinals of the 1999-2000 Champions League tournament. It was no surprise that other teams began experimenting with the 4-2-3-1 after Real’s upset, but the formation really didn’t take off in England until former Valencia manager Rafa Benítez led Liverpool to win the 2004-2005 Champions League.

At the 2010 World Cup, 27 of the 32 teams used the 4-2-3-1, although most used a more defensive version than Spain’s possession-based tactics. Tactical flexibility was even more evident at the 2014 World Cup, where out of the top six teams, two used a 4-4-2, two used different formations depending on the opponent, and two used a 4-2-3-1, including winners Germany.

4-2-3-1 just might be the new standard, mostly due to its flexibility. Player roles are defined, yet the formation itself is adaptable, and can absorb new players who haven’t yet had a chance to gel with their team. The 4-2-3-1 is designed to outnumber the opposing team in the midfield area, where mistakes can easily be made, and allows for quick movement on both defense and offense. The three attacking midfielders plus one striker can push up and attack from all angles while the two defensive midfielders can eliminate the space between the back four, who can push up or drop back as needed.

Those two defensive midfielders, known as a “double pivot,” is the key feature of the 4-2-3-1. The 4-4-2 uses only one holding midfielder to control the space between the back line and the attacking midfielders, making it difficult for that one player to really have any control over the tempo of the game. The double pivot, on the other hand, incorporates one midfielder who can hold it down defensively, allowing the other midfielder to drop back and protect the backline, or move up to support the attacking midfielders, ideally dictating the pace of the game. Chelsea’s success as the 2014-2015 Premier League Champions was down to the dynamic of their double pivot. Nemanja Matić provided the defensive stability while Cesc Fàbregas supported the attacking midfielders. With neither as sharp this season, it’s little wonder Chelsea failed to challenge for the title.

Jürgen Klopp’s Borussia Dortmund exemplified how to run a modern 4-2-3-1 well. Now known as gegenpressing, it involves winning the ball upfield for quick scoring opportunities. Klopp’s Dortmund included a ball-winning midfielder in the double pivot (for example, Sebastian Kehl), fullbacks who could provide width (Marcel Schmelzer and Łukasz Piszczek), and a forward (Robert Lewandowski) who could essentially do it all. While the fullbacks remained wide, the rest of the team stayed tight together and swarmed the ball, outnumbering their opponents. The central midfield crammed the middle, allowing fullbacks to take advantage of the space. Of course, this only works if your team has a ridiculous level of fitness – and the perfect players to fill the slots. Dortmund’s struggles in the 2014-15 season exemplify the difficulty of running this tactic without the right talent.

The 4-2-3-1 with a solid double pivot is also one of the easiest ways to counter the false-9 (when a forward drops back into the midfield rather than staying high, thus forcing a midfielder into covering), because one defensive midfielder can mark the false-9, leaving the other free to cover the space.

Conversely, the rigid 4-4-2 can create pockets of space around the field, leaving huge passing lanes for opponents to take advantage of, and midfielders can be isolated and overwhelmed. The diamond 4-4-2 allows for more flexibility in play, but its roles can be more complicated, so if a player is out of position the whole thing can easily fall apart. Players, especially midfielders and fullbacks, still need to be able to cover a lot of ground , while central midfielders need to be particularly disciplined, or risk being caught out, leaving big gaps that the other team will almost certainly capitalize upon.

At the end of the 2015 MLS season, 11 of the 20 teams were using a 4-2-3-1, though its effectiveness depended on the skill level of the players. In three of the past five years, the LA Galaxy won the MLS Cup using a 4-4-2, but as the 2016 season begins to take shape, many teams are exploring other options. Of the top 12 teams at the end of April, four were consistently running a 4-4-2. Two of the eight others have used a 4-4-2 at least once this season, but most are using a 4-2-3-1 or a 4-3-3. Some squads also employ different formations depending on who is on the field; for example, Toronto FC tried a 4-4-1-1 with Jozy Altidore up top.

The Seattle Sounders began its eighth season by signing a wealth of talented strikers: Jordan Morris, Oalex Anderson, and Herculez Gomez all came to Seattle this year. Now Sigi Schmid, not the most tactically creative of coaches, has Seattle trying to play a 4-3-3. But the Sounders’ struggles reveal what happens when the 4-3-3 is not running the way it should. Partially because Schmid is depending on a few standout players to carry the team, many of whom have been injured off-and-on this season, but also because he is trying to force a square peg through a round hole. Instead of looking at what formation might be best for the talent he has, and using that talent strategically, Schmid is trying to find a way to get all of his best players on the field at once, and it’s not working so well.

Second-year teams Orlando City SC and New York City FC are looking to improve on their inaugural seasons (neither made it to the playoffs), so, in order to allow their star players to really shine, both are experimenting tactically. NYCFC brought in a new manager, Patrick Vieira, who is hoping an unorthodox formation (like a 3-4-3 or a 3-5-1-1) will better showcase the talent and creativity of Frank Lampard and Andrea Pirlo.

Orlando City already has some strong players (like last year’s Rookie of the Year Cyle Larin, and Darwin Cerén, and Kaká) and Adrian Heath has been testing a 4-3-3 and a 4-2-3-1. The addition of Brazilian Julio Baptista gives Orlando City more depth offensively, leading Heath to try both Baptista as a lone striker and a Baptista/Larin combo at the top. The team is doing okay so far this season, and running the 4-2-3-1 allowed new-to-the-club Antonio Nocerino to jump right in without spending a ton of time training with the team.

While attempting to find formations that incorporate all their stars isn’t working so well for these teams (at least, not yet), many of the top teams are using the 4-2-3-1. While LA won the MLS Cup using a 4-4-2 in 2011, 2012, and 2014, Sporting KC won with a 4-3-3 in 2013, as did Portland last year. This season, LA was busy in the transfer market, bringing on players like fullback Ashley Cole and defensive midfielder Nigel de Jong, and has been testing out new formations to find a fit for the new stars. In four games that LA has played a 4-4-2, the side scored just four goals (and scored zero in two of those games) yet scored an impressive 13 goals in three games played in a 4-2-3-1.

If a team playing a 4-3-3 (or its close relative, the 4-2-3-1) takes a trophy again this year, especially if it happens to be a traditionally 4-4-2 team like LA, it could very well signify the end of the 4-4-2 era in MLS.