Article by Ben Griffis

The back 3, after being popular in the early 1900s before losing steam in the 30s (Wilson, Ch. 3), made a comeback in the 80s (Wilson, Ch. 16). In the 80s and 90s, the central center back was typically a sweeper or libero like Franco Baresi, Franz Beckenbauer, Morten Olsen, and Ronald Koeman.

In the 2000s, especially the 2010s, the back 3 gained further support, with managers like Louis van Gaal using three center backs with the Netherlands and Manchester United and Antonio Conte with Juventus, Chelsea, and Inter. Modern back 3s don’t typically employ a sweeper or libero, but rather use on a deep lying play maker and center backs with great vision and ball control.

Even though managers like van Gaal and Conte have led the resurgence of the back 3 in today’s game, few countries deploy the system to the extent that South Korean clubs do. While a couple clubs in most European leagues use back 3s, if you were to flip on a match from either of South Korea’s two professional leagues (K League 1 & K League 2), chances are at least one—if not both—clubs would be using a back 3.

In fact, as of the time of writing, after all teams have played between 18 and 21 games (because of COVID-19 postponements), only four of the 22 teams in the leagues have not used a back 3. Further, six clubs have only used a back 3. Of those six teams, five are in the top-flight K League 1—Suwon Bluewings, Gangwon, Jeju United, Daegu FC, and Seongnam. Bucheon is the only K League 2 side exclusively using a back 3 this season.

Overall, as the visualizations in this article will show, a back 3 has been used 53.1% of the time in K League 1 and 57.6% of the time in K League 2. If we combine the two leagues, South Korea’s professional leagues use a back 3 55.3% of the time. So, statistically speaking, if you watch a South Korean professional game, you’ll see a back 3. This article discusses South Korea, and in the future I would like to do the same analysis in major European leagues to compare.

K League 1

First, let’s look at the K League 1’s formation data. Because of COVID-19 postponements, all teams have played between 18 and 20 matches after round 20.

Sorted by number of times used (the grand total row at the bottom), we see that the 4-5-1 is the most popular formation used in K League 1—but just barely. Closely following is the 3-4-3, and rounding out the most popular formations is the 3-5-2. Most of the time, the 4-5-1 is, like Pohang’s tactic, a 4-2-3-1. However, because of the fluidity of all formations I kept this as a 4-5-1. Further, the 5-4-1 used once by Seongnam was counted as a back 3 for ease, as it still uses 3 center backs and is sometimes difficult to differentiate. say, a 3-5-2 and a 5-3-2 s the wing backs’ position will change the shape.

This table also shows what teams have tended to stick with a single formation for all or most of the season. Teams like Daegu and Jeju have only used a 3-4-1-2 and 3-4-3 respectively, while others like Suwon FC, Jeonbuk, and Seongnam have used a large spread of formations.

This pie chart shows us that a back 3 or back 5 is the most popular system in the league, even though the most popular formation employs a back 4. 53.1% of the time, a K League 1 side starts in a back 3 or 5. And as the table above shows, it’s not just a few teams using a back 3 for the whole season. Nine of 12 K League 1 teams have used a back 3 at some point in the season.

Now that we know which formations are the most popular in K League 1, let’s looks at how they have performed.

This table shows us the average points per game each formation earns. The formation earning the most points per game is the 3-4-1-2, which only Daegu FC have used. This means the average points per game is equal to Daegu’s points per game and they are currently in 4th and 2 points off leaders Ulsan. It looks like Daegu and manager Lee Byung-keun have come up with the best formation all season and stuck to it.

Outside of the 3-4-1-2, a 4-4-2 earns the most points on average, with 1.7 per game. Seoul, Jeonbuk, Pohang, and Suwon FC have all used this formation, combining for a record of 5-2-3 (w-d-l). Several formations are close in performance after the top 2, and they vary in popularity from the 3-1-4-2 used eight times by Seongnam to the 3-5-2 used by all but five teams at some point this season.

Of the most-used formations, the 3-4-3, used mainly by Jeju and Gangwon in 8th and 9th respectively, fares the worst.

Finally, here is a dashboard showing the entire K League 1 analysis. Overall, it seems Daegu have the best formation, but no other team has attempted to emulate their success.

K League 2

Now let’s see K League 2’s data. All teams in this league have played 21 matches now that the previously-postponed games have been made up.

The 3-4-3 is the most popular formation in K League 2 by a fair margin, followed by the 4-3-3 and then the 3-5-2. Just like in K League 1, two of the top three formations are back 3 systems, showing its popularity in South Korea. Of the 10 teams in the league, only Gyeongnam have not used a back 3 at all this season, favoring a 4-3-3 or 4-4-2.

Bucheon are the only K League 2 team that have only used a back 3 all season, typically lining up in a 3-4-3 but also using a 3-5-2 once. Interestingly, outside of Gyeongnam, Busan IPark have used a back 3 the least—yet they still used a back 3 in 10 of their 21 matches. While back 3s are very popular in K League 1, they’re even more popular in the second division.

The pie chart for K League 2 really puts it into perspective. 57.6% of all formations used this season have been back 3s. Going back to the anecdote at the beginning of this article, if you turn on a K League 2 match, you’re almost guaranteed to see a back 3. Your best bet to avoid seeing a back 3 is to watch Gyeongnam and Busan IPark, hoping Busan don’t employ their most-used formation (3-4-3).

Now let’s look at K League 2’s formation performances.

Unlike K League 1, the K League 2’s best performing formations are rarely used. Interestingly, second-from-bottom Chungnam Asan are the only team to use both of these formations—and have earned points with both as well. Since Asan have used a remarkable 7 different formations, and none more than 5 times, perhaps they should look into lining up in either a 4-1-4-1 or a 3-1-4-2.

The popular formation that performs the best is a classic 4-4-2. Taken together with the K League 1 data, the 4-4-2 shows why it’s such a tried and tested formation. Next, the 4-3-3 performs well as well, with 1.52 points per game. The most popular formation, 3-4-3, only earns 1.19 points per game, but this number is slightly brought down by the two worst sides currently—Bucheon and Asan—being its two biggest users.

And here is a dashboard showing K League 2’s information.

South Korean Professional Leagues Combined

Now let’s see what the combined K League 1 & 2 data looks like.

Here we can see that the 3-4-3 is, by far, the most popular formation used in South Korean professional football, being used 115 times. The second most popular formation is another Back 3, the 3-5-2, being used 81 times. The third most popular formation, and most popular back 4, is the 4-3-3 and it has been used 71 times so far this season.

Taken together, back 3s (and one back 5) make up 55.3% of all formations used in the K League 1 and 2. Performance-wise, however, a 4-4-2 will earn the most points on average. Of course, since we’re combining data from two different leagues, this does not mean as much as when comparing within one league. But regardless, rounding out the top 3 best-performing formation are two Back 3s, the 3-4-1-2 and 3-1-4-2.

Is South Korea the Back 3’s Stronghold?

Based on this season’s data, South Korea truly is where the back 3 shines. The back 3 thrives amongst most teams across both professional tiers of South Korean football, although the team leading K League 1 so far—Ulsan Hyundai—exclusively employs a back 4.

This final image shows each club’s use of a back 3 or back 4 throughout the current 2021 season. 12 of the 22 clubs use a back 3 more than 50% of the time, although 2 of the top 5 K League clubs at the time of writing do not use a back 3 at all, Ulsan and Pohang.

In the future I would like to gather info on other leagues to compare and see if there are other leagues where the back 3 flourishes, and how they compare to South Korea’s leagues.

But in the meantime, we can see that the back 3 is the most popular system in South Korea, with 53.1% of all formations used in K League 1, and 57.6% of all formations in K League 2.

Seoul: The Heart of the Stronghold?

A final interesting piece that arises when looking at the K League’s formation data is the geography of the clubs who use back 3s. Only 2 of the 9 clubs in the Seoul and Gyeonggi-do provinces primarily use a back 4—FC Seoul and Suwon FC. the other 7 all mainly use a back 3. Of the 13 remaining clubs outside the Capital Area, only 5 primarily use a back 3.

So, Seoul area clubs mainly use a back 3 while clubs outside Seoul tend to prefer a back 4. While this does not mean anything statistically, it is a fascinating piece of information in the context of this article. There must be something in the water—or perhaps there’s a café managers meet at like they did in 1930s Vienna to discuss cutting-edge tactics. Either way, it appears that Seoul is the beating heart of the back 3’s stronghold.

References
Wilson, J. (2013). Inverting the pyramid: the history of soccer tactics. Bold Type Books.