A team can be described as playing one shape by one observer and a different one by another, with both being accurate. The wide forwards are usually the reason.
The wide players occupy two positions
In possession, wingers advance to threaten the opposition defensive line, which puts three attackers across the front and produces the familiar attacking description.
Out of possession, those same wingers drop alongside the central midfielders to form a defensive line of four, and the front line reduces to the striker alone.
Nobody has been substituted and no instruction has changed. The shape is phase-dependent, and the two descriptions capture different moments.
The single pivot stays constant
Both descriptions include one holding midfielder in front of the defence, which is the fixed point around which the rest rotates.
That player's job does not change between phases, screening the space in front of the centre-backs in defence and offering the first pass out in possession.
Because his position is stable, he is the most reliable landmark for identifying which system a team is actually running.
The difference shows in where the press starts
A team pressing high keeps the wide forwards advanced, which makes the front three visible and the shape look like an attacking one even without the ball.
A team defending in a mid or low block pulls them back immediately, and the same personnel produce a compact two-bank structure.
The choice reflects the opponent and the game state rather than a change of system, and it can shift within a single match.
The trade-off is the space in front of the pivot
With the wide players high, the holding midfielder is left with a large area to cover on his own, and opponents attack the gaps either side of him.
With them dropped, that area is protected but the team has no pressure on the opposition's build-up and concedes possession freely.
Coaches manage this by defining when the wide players press and when they recover, usually tied to where the ball is rather than to a general instruction.
Why the labels still matter
Describing a team by its defensive shape tells you what it is trying to protect; describing it by its attacking shape tells you where it intends to threaten.
Neither description alone is sufficient, which is why analysts increasingly write both and treat the pair as the actual system.
For a coach preparing against such a team, the useful question is not which label applies but how quickly the wide players get back, since that determines whether the flanks are available.