The Pulse Behind the Screen: VAR, xG and the Limits of Numbers in Vietnamese Football

The Pulse Behind the Screen: VAR, xG and the Limits of Numbers in Vietnamese Football

In the 74th minute, the referee raises two fingers to the earpiece and turns toward the monitor at the corner of the touchline. The stadium goes quiet. Not the held-breath quiet of a crowd waiting for a goal. A different quiet — the quiet of a hospital corridor when someone pushes open a door and says the results need to be checked again.

In my second notebook, the one I keep for things that have nothing to do with tactics, I wrote three words that night: waiting, and silence.

The fans below me opened their phones. The screen light came back up onto their faces, blue and white. They were not rewatching the incident. They were reading what other people were already writing about the incident. In those forty seconds, forty thousand people switched from watching football to watching an argument about football. When the referee raised his arm, nobody was surprised. Everyone already knew the outcome, because everyone had read the outcome thirty seconds earlier.

That moment made me think Vietnamese football is going through a much larger change than simply gaining a new refereeing aid. We are changing the way we believe.

I am a training-ground observer. Twenty-one years ago I started at local radio stations, reading out lower-division results to people who could not get to the ground. In 2026, at thirty-one, I left a web sports editor job to become an official training-ground observer for Busan IPark in K League 2. Since then I have lived in Busan, writing about Korean football for Korean readers and occasionally about Vietnamese football for Vietnamese readers. There is a gap between those two jobs that I have never fully explained to anyone.

There are things that never show up on the scoreboard, and they decide everything. I wrote that in my first notebook, the tactics one, in September 2026, and I still have not found a sentence to replace it.

A screen, and what it cannot see

VAR entered V.League 1 in the 2026 season, following the roadmap set out by the Vietnam Football Federation and the Vietnam Professional Football Joint Stock Company. At the time, most of the online debate in Vietnam circled a single question: would refereeing errors go down.

I did not think that was the right question. After three seasons watching from a distance, I am more convinced of what I thought at the start.

VAR does not make controversy disappear. It moves controversy off the pitch and into a closed room, and it converts controversy into a technical argument — one that only insiders are qualified to have.

Before VAR, when a decision was disputed, a fan could point at the stand and say the referee got it wrong. A simple claim anyone could make. Now, when a decision is disputed, the argument drops immediately into concepts most spectators have never been trained to parse: what counts as a clear and obvious error, what counts as interfering with play, how many metres away a handball has to be before it is unavoidable, which frame the shoulder and knee lines are drawn on.

That is a transfer of authority. The right to argue moves from the stand into the review room. Fans still have feelings, but those feelings no longer have a legitimate place to be expressed. They are forced to trust a conclusion produced by someone else, based on footage they never fully see.

In V.League there is a technical detail rarely mentioned in online arguments. The number of cameras at each match is not the same across leagues. A Premier League match can be captured from more than thirty angles. A V.League match has far fewer. That means the same incident, the same law, the same referee trained to the same curriculum, can produce different outcomes — simply because one league can afford more viewpoints than the other.

The certainty of VAR depends on how many cameras your league can afford to hire. That is an economic fact presented as a fact about justice.

I do not say this to dismiss VAR. I say it because I stood in the mixed zone in Kazan on 27 June 2026 after South Korea beat Germany 2-0, and I heard the Korea head coach say his team won because the players trusted each other. Nobody in that press room asked him about technology. Nobody asked about data. Everyone asked about trust.

I wrote that line down in pencil, because my pen had run out. I still keep the sheet of paper.

xG, and the habit of translating feeling into percentages

Alongside VAR, another thing has entered the Vietnamese football vocabulary over the past five years: expected goals.

I object to how it is being used, and I want to be precise about why.

The metric was born from a need to assess chance quality across a large dataset. It was built by reviewing hundreds of thousands of shots — location, angle, type of pass that preceded it, number of defenders in front — and calculating a scoring probability for each. That is serious work. I do not object to the work.

I object to it being turned into an answer.

The metric measures chance quality through a model trained on other people's data, and it does not know what the player taking that shot is thinking.

Three years ago I sat in a café near Asiad Stadium reading an analysis of a match I had watched in person. The piece concluded that the losing side deserved to win. The argument rested on the metric. I read to the last line and realised I had no way to push back in the language of the piece. My feeling about that match — that the winning side played the way the night demanded, against that specific opponent, in that specific atmosphere — did not count as a form of evidence.

That is what worries me most. Not that data is wrong. That data becomes the only recognised form of evidence, and everything else becomes personal opinion.

In my tactics notebook I record sessions in an odd way. I do not note how many metres a player ran. I note which direction he ran, at what moment, after a teammate shouted at him or after a teammate praised him. Sometimes I note the weather. Busan summers are humid enough that the ball travels slower. A shot in the 80th minute in that air is not the same as a shot in the 80th minute in dry air. No model accounts for that.

I know what I do is not science. I am not trying to do science. I am trying to do record-keeping.

Four points, and a dressing room

My first season as a full training-ground observer was 2026 with Busan IPark. The team played thirty-six matches in K League 2, scored fifty-two goals, finished third, four points short of promotion.

Four points. One win and one draw.

I sat in the stands at Asiad Stadium through that whole season, recording every tactical session under coach Kim Do-hoon, particularly the 4-2-3-1 he introduced in March. I tracked Lee Dong-jun, number 11, improving week by week. By October I could predict his choice in about seven out of ten situations.

In the same period I noticed instability in the dressing room between two foreign players. Not a fight. Not a statement. Small details: one not passing to the other when an alternative existed; the other not sharing a lunch table; a sentence left unfinished in a corridor. I wrote all of it in my private journal. I did not dare say it out loud.

At the end of the season the team was four points short. I cannot prove that instability caused it. No metric measures the distance between two people in a dressing room. But I was there, and I know what I saw.

An empty stadium, and I can still hear the match's pulse.

The lesson from that season was not tactical. It was about knowing what I do not know. I do not know whether those two players reconciled. I do not know whether the four points were a consequence. But I know that if I had written an analysis based only on goals and points, I would have skipped the most important thing I witnessed that year.

Kazan, Jakarta, and two ways of defending

In June 2026, on the strength of three years covering Korean football, I was sent to Russia for the World Cup. I was in Kazan when Kim Young-gwon scored in the 90th minute plus three. I heard the scream from a small section of the stand, a few hundred Koreans sitting among tens of thousands of others.

Two days later I flew to Jakarta to follow coach Park Hang-seo and the Vietnam U23 side for two weeks, recording how he used a back three with four midfielders and three forwards, shifting shape by opponent.

Two football cultures, two ways of defending, one root philosophy. Korea defended by pulling the opponent into a tight space and countering in the final instant. Vietnam under Park defended by holding the distance between lines, accepting life without the ball, and waiting for one moment.

Neither can be fully explained by data. Both are explained by trust between people who play together. That is why the Korean coach's line after Kazan stayed with me so long.

January 2026

In January 2026, Vietnam won the ASEAN Cup, beating Thailand over two legs by an aggregate of 5-3.

I watched from Busan, on a screen, in an apartment roughly three thousand kilometres from home. The Koreans around me were not watching. The Vietnamese in Busan were. A small restaurant near Busan Station filled up on both evenings. I sat in a corner, taking notes as usual, and realised I was not taking notes about the match but about the people around me.

There was a man of about sixty, a factory worker who had not been back to Vietnam in twelve years. When Vietnam scored their third goal in the second leg, he cried. Not loudly. Just tears, wiped away with the back of his hand.

A Korean crying over Vietnamese football. That is the shared pulse. I wrote that line in my notebook and never used it in a piece until today.

When the system returns zero

There is something in my trade I want to put on the record, even though it sounds technical.

Sometimes, after gathering material for an analysis, I open the folder and find it empty. Not empty because I was lazy. Empty because the source gave nothing. A match with no detailed data. A press conference nobody recorded. A report with its opening cut off.

There are two ways to handle that. The first is to write an analysis from what you think you remember. The second is to write in the notebook that there is nothing there.

I have chosen the second many times. Every time, an editor has asked me why the piece was so short.

I think this is the central problem of football analysis in an age when anyone can publish. The system rewards certainty. A piece that asserts strongly gets more engagement than one that says the data is not yet sufficient. A clear conclusion is easier to share than an admission. So the pressure always leans toward inventing a conclusion.

A system that can say it does not know is more trustworthy than one that always produces a conclusion. In football, that is true of people as well as software.

I wonder whether we could accept a football commentary culture in which, occasionally, a piece is three lines long and says: I do not know yet.

The contrary view

What most people believe about data in football is this: more data, more clarity. I think the opposite is true more often than not.

More data means more places to argue. A match with three metrics has three talking points. A match with thirty metrics has thirty, and each demands a level of expertise most fans have no time to acquire.

The result is a paradox. We have more information about football than we did twenty years ago, and less capacity to talk about football together. The conversation fragments into small groups, each speaking its own language, with no interpreter between them.

I think this is the real reason referee arguments have become harsher. People no longer feel entitled to speak about a decision, so they shift from criticism to accusation. When you cannot discuss the law, you discuss motives. And when you discuss motives, you are no longer discussing football.

Another contrary view concerns how we judge Vietnamese football's development. I often hear that adopting VAR shows the game has progressed. I am not sure. It may. But it may also be a way of avoiding slower work: training young referees in the provinces, improving pitches in the lower divisions, paying players in the first and second divisions enough to live on, building a youth league with a stable calendar. None of that looks good on camera. Nobody films it. And it takes ten years to show results.

Technology produces images immediately. That is why it gets priority, and why I keep a certain suspicion of it.

The same applies to another field I follow: esports. There, integrity rules are falling behind the speed of money. A traditional football league takes decades to build a rulebook. An esports competition can have millions of viewers within months, with a thin rulebook. That gap is where risk lives.

What I will be watching

Three signals.

First, the number of cameras per V.League match. It is rarely published and rarely discussed, but it sets the ceiling on every refereeing conclusion. If that number rises, the quality of debate rises with it.

Second, how Vietnamese football outlets use data. If within two years analyses start making room for the unmeasurable — dressing-room atmosphere, travel schedules, a player's family situation — that is a sign of maturity.

Third, the number of young referees trained in provinces outside Hanoi and Ho Chi Minh City. That is the dullest of the three signals, and the most important.

From Busan to the World Cup, I have learned that football does not lie. But football can be made to say something different, by people with an interest in telling a tidier story than the facts allow.

On the last day of the 2026 season in Busan, I stayed at Asiad Stadium after everyone had left. The lights went out section by section. No crowd. No cameras. Just a groundskeeper walking the touchline with a very loud mower. I sat in row five and wrote the final lines of the season.

What I wrote in those ten minutes never appeared on any page. It was the most complete piece of note-taking I have ever done.

Not every match has a crowd. But every match has someone keeping its pulse. I think that is my job: not to say what the match meant, but to record how it happened.

And if there is one thing I want to say to the people writing about Vietnamese football today, it is this. When the material is empty, write that it is empty. That is not failure. That is the most accurate data you have.

Because in a football culture learning to trust numbers, the person willing to say they do not yet know is the one keeping the pulse for everyone else.

An empty stadium, and I can still hear the match's pulse. And I will keep sitting there, with two notebooks, until that pulse stops — if it ever does.