As usual you've got to have your finger on the button to enter this one.
Think it opened at 10am last year and was full by 12.
(I entered at 9.30am along with hundreds more, so always worth a try beforehand)
This year Knavesmire site is saying entries open on-line at 7am on Sat 20th.
www.yorkknavesmireharriers.co.uk/
Maybe this early time wil reduce the rush.
DW