Entry to most professional tournaments is determined by ranking on a specific date, often weeks before the event. That single snapshot carries more consequence than any other point in the calendar.
Why a snapshot is necessary
Organisers must know their field in advance to arrange accommodation, produce schedules, brief broadcasters and process accreditation and visas.
Rankings change weekly, so a continuously updated entry list would leave the field unsettled until the tournament began, which no organiser can work with.
The cut-off freezes the list at a defined moment, after which the field changes only through withdrawals and the promotion of alternates.
How competitors plan around it
Because the date is published, competitors know exactly which events fall inside the window that can affect their position for a given tournament.
Some enter additional smaller events specifically to gain points before a cut-off, accepting extra matches for the chance of a place in a larger draw.
The decision involves risk, since additional matches carry injury exposure and a poor result may also cost points being defended.
What happens between cut-off and play
A competitor may improve substantially in the intervening weeks and still miss the draw, because the list was fixed before those results occurred.
Conversely, someone who qualified on the cut-off date retains their place even if their form collapses afterwards, since entry is not reassessed.
Wildcards exist partly to correct the sharpest cases, allowing organisers to admit a competitor whose recent form the cut-off failed to capture.
The alternate list
Competitors just outside the cut are ranked as alternates, entering in order as withdrawals occur, sometimes on the morning of the first round.
They must travel and prepare on the possibility of playing, which is a substantial cost for those with limited funding and no guarantee of a match.
Qualifying draws serve a similar function lower down, offering a competitive route into the main draw for those outside the direct entry cut.
Why the date is set where it is
Placing the cut-off close to the event improves accuracy but leaves little time for logistics, particularly where visas are required.
Placing it early simplifies operations but widens the gap between the field selected and the field that current form would produce.
Different tours resolve this differently, which is why the same competitor can be inside the cut for one event and outside for another in the same month.
