All new watches are keyless operation, old watches used to use a key to set time, date and wind the watch. Then one Philip Patek invented the system we used today of doing all that with the crown.
'Those without a sense of the history of the mechanical watch probably do not know that were it not for the innovation of Patek Philippe in 1841--with the invention of the "keyless works"--we might still be winding and hand setting our wristwatches with a key. Although now taken for granted, the crown and associated gearing of the modern watch--which, miraculously, both winds the watch and sets the hands--is an extremely clever piece of engineering. One measure of the success of the design is that the virtually the same concept is used in every mechanical wristwatch produced today.'
Or thats what i've known the keyless phrase as, i could be very wrong