Probably the biggest factor in this Cheltenham is the ground. Nearly all of this season's form has been recorded on varying degrees of soft, heavy and bottomless ground. There has been so little rain of late that the going is Good, far quicker than all of these horses will have been running on recently.
Plus many horses are trained and prepared with Cheltenham in mind and only reveal their true abilities at this stage of the season.
Plus... the handicap system (which is not applicable to every chelt race) means that theorteically the hroses should finish in a line...
The fact that the winner is never obvious is one of the attractions of Cheltenahm, and what makes it so fiendishly difficult.
If you look at a card in most meetings through out the rest of the NH season, it is straightforward to find winners and reasons. At chelters you can find five or six winners in every race