After Manchester United’s goalless draw with West Ham in December, Louis van Gaal professed himself baffled by the Old Trafford crowd’s demands for his side to be more attacking. “I don’t understand that they are shouting ‘attack, attack’ because we are the attacking team and not West Ham United,” he said. In doing so, he raised a question that seems fundamental to football and yet is surprisingly hard to answer: what is attacking?

“We,” Van Gaal went on, “are always more dominating than our opponents. When we have a lot of ball possession, you have a lot of ball possession to create chances and not to play the ball around and don’t score.” So for Van Gaal, having the ball is attacking; he believes goals will come from possession. “My opinion about scoring goals is not only compulsion but also a lot of luck,” he said.

The aspect of luck is clearly important. There are games in which one team plays superbly, have 20 chances and fail to score, maybe because of a striker who is out of sorts, or thwarted by a goalkeeper in inspired form, defenders popping up on the line, the ball hitting the post and bouncing out not in. That happens. Goals alone aren’t a measure of how attacking a side is (although clearly there is a correlation, particularly over longer periods of time).

United against West Ham had 21 chances, but no one – Van Gaal perhaps excepted – could realistically claim they had played great attacking football. Only one of the chances resulted in a shot on target, which at the very least suggests United weren’t attacking efficiently. It’s telling that eight of their shots came from outside the box (and three more right on the edge), and that eight were the result of set plays. Their way of attacking wasn’t creating good chances. The problems have continued since then – just four goals in the following five league games, even if those matches yielded 21 shots on target between them.

But even to talk of a number or quality of chances seems the wrong way round. That’s the result of attacking, not the cause of it. So while we may know what attacking looks like – goals, shots, chances, crosses, etc – is there any way of categorising the approach that may lead to that?

Proactive v reactive

Germany counterattacked brilliantly at the 2010 World Cup but some fans objected to the tactics being described as reactive. Photograph: Christophe Simon/AFP/Getty Images

Perhaps most simply, football can be divided into proactive and reactive approaches – playing with the ball, looking to control possession against playing without the ball, looking to play on the counter. Yet even that is more complicated than it may at first appear.

During the 2010 World Cup I wrote a piece in which I pointed out that Germany were a reactive side who counterattacked brilliantly. That prompted unusual fury below the line; one commenter accused me of being a Russian plant. Reactive, it seemed, was perceived as an insult, counterattacking seen as pejorative.

That, surely, has now changed. Jürgen Klopp’s Borussia Dortmund showed how stirring counterattacking can be, while many came to find the relentless possession football of Spain wearisome. But that’s where the association of proactive/reactive with possession/non-possession starts to fall down. For one thing, Van Gaal’s United had 58% possession against West Ham, yet fans clearly didn’t think that was attacking.

And for another, pressing – the organised hounding of the opponent in possession – is about as far from being reactive as it’s possible to get. You can counterattack by sitting deep and waiting for the ball to come to you, or you can counterattack by chasing the ball high up the pitch. Counterattacking, it turns out, can be reactive or proactive.

Not only that, but Van Gaal’s sides (and this is not only true of United) often manage to be reactive with the ball, their risk-averse probing being as reliant on the opposition making a mistake as José Mourinho at his most possession-averse.

The ball

Without the ball Real Madrid’s expensive attacking talents cannot hurt sides, as Barcelona showed in winning 4-0 in November. Photograph: Daniel Ochoa de Olza/AP

Shortly before the 2014 World Cup, I was on the panel at a Blizzard Q&A where an audience member insisted that what he wanted from England wasn’t necessarily to win but just to be attacking. I asked him what he meant and he talked about getting more exciting attacking players in the team. Which I suppose is reasonable enough. But the problem is, before those exciting players can do any attacking, they have to have the ball – a lesson Florentino Pérez, for instance, seems never quite to learn.

The issue of how to get the ball comes back to the issue of proactivity and reactivity. If your players are good enough, you can have it and keep it, like a Van Gaal side, and assume that the attritional process of passing will wear an opponent down. You can sit deep, rely on your defenders or your defensive shape being good enough to win possession and then counter, with the advantage that an opponent on the attack is likely to be off-balance and to have left space that can be exploited. Or you can press, go hunting possession, again with the advantage that a quick transition is likely to be more productive than attacking a defence that is set.

Most commonly, of course, teams do all three, but in varying proportions. In the Premier League this year, it’s notable how much more common the latter two are than the former, something that probably in part goes towards explaining why home advantage is apparently so much less significant than it was. Counterattacking has become more common than attacking – although even there is a complication in that a recognition of the value of counterattacking means that the counter-counter – of which gegenpressing is the most proactive and celebrated example – has also grown in popularity with the result that the number of goals scored on the counterattack as actually fallen over the past decade.

Risk

Manchester United attempted 81 crosses during a Premier League match against Fulham in February 2014 but still failed to win the game. Photograph: Andrew Yates/AFP/Getty Images

You can play breathtakingly exciting football with 40% of the ball and desperately dull football with 60%. You can be boring with 20 chances and thrilling with five. More than outcomes, perhaps, what is important is mood. This is Sjaak Swart’s point. “I never gave the ball back to my defence, never!” the Ajax winger of the 70s told David Winner in Brilliant Orange, complaining about how Ajax’s wingers in the 1990s, Marc Overmars and Finidi George, would check back if faced with two opponents. “It’s unbelievable! But that was the system with Van Gaal. Many games you are sleeping! On television, they say: ‘Ajax 70% ball possession.’ So what? It’s not football. The creativity is gone.”

He wanted the wingers to take on the defenders, to risk losing the ball. United fans now who speak of the classic United style – and clubs’ styles are always hard to pin down – seem to mean a game based on width and getting crosses into the box. But crosses also risk losing the ball. The joy of Klopp’s Dortmund at its best is how quickly the team got the ball forward, even though that risked losing possession.

Yet take each of those three points in turn and it’s evident that none in itself is a panacea. Dribble too much and you end up with a mannered, individualistic game not unlike football in the 1860s and 1870s before the Scots invented passing. Cross too much and you end up like David Moyes’s United against Fulham in February 2014, attempting 81 crosses without anything to show for it. Get it forward too quickly too often and you end up with the brainless long-ball nonsense that has blighted English football for so long; there’s a backlash in Argentina, for instance, against Marcelo Bielsa partly because so many teams in the Primera now play too quickly and too directly, conforming to Bielsa’s vertical tenets without the tactical organisation to make it effective.

Balance, clearly, is part of it, but there must also be intelligence: endlessly repeating the same trick may have attacking intent, but the effect is tedium. There must be some kind of risk, but equally there needs to be a platform to support the risk-takers. Short passes can be attacking, but so can long. Playing with the ball can be attacking, but so can playing without. Proactive football can be attacking, but so can reactive. Dribbling can be attacking, but so can an approach based almost entirely on passing.

Attacking is, like so much in football, nebulous, and is largely dependent on context. In the end, attacking becomes like pornography in Justice Potter Stewart’s famous description: it’s hard to define, but you know it when you see it.