The allocation of weights for the 2006 Grand National marks a pivotal point for the prospects of trainers, jockeys, owners and punters.
A maximum field of 40 will contest the John Smith's Grand National
It can clear the path to big-race glory or produce a burden too heavy to overcome.
BBC Sport weighs up the factors involved in preparing for the Aintree marathon on 8 April.
Unlike the other most prestigious steeplechase of the year, the Cheltenham Gold Cup, the Grand National is a handicap race.
This means horses carry differing weights according to their previous form.
The idea behind a handicap is to make for a more even race - the handicapper's ultimate (though in practice unfeasible) aim is for the horses to pass the winning post in a dead heat.
Handicapper Phil Smith must take a variety of factors into account, including:
Form: Horse's recent and previous performances
Course: The so-called 'Aintree Factor' - does the horse like the track?
Distance: Is the horse proven over long trips?
Quality: Attract the best horses to the race
The "best" horse in the race is given the top weight (about 11st 12lbs) and the weights allotted to the other horses are set in relation to this.
This means if the top-weighted horse drops out, the weights of the other competitors may alter but will not change in relation to each other.
The Grand National is a test of endurance over four-and-a-half miles and Hedgehunter in 2005 was the first horse since Rhyme 'n' Reason back in 1988 to win carrying 11 stone or more.
Backing a short-priced runner on the day weights are published in February has been a quick route to the poor house in recent years.
Only Seagram, Lord Gyllene and Earth Summit of the last 11 Aintree winners were quoted at 20-1 or shorter by William Hill at the time of publication of the handicap.
Notable hot ante-post favourites turned over include Master Oats, Young Kenny
and Carvill's Hill - who did not even give his supporters a run for their money
Horses can also run in other races in between the handicap being set and the race being run.
Seasoned punters look out for these runs as a chance to spot horses whose talent may not have been accurately reflected by the handicapper.
For example, when the handicapper allots a weight to a horse for the Grand National, he will look at its previous form.
But if a horse had been run over the wrong distance, or was simply below par on a given day, that would not be a true indication of its potential.
It may then run at a more suitable distance and perform much better after the handicap had been set, but before the National itself.
The horse would then be said to be carrying a favourable weight in comparison to its rivals.
There are exceptions - some valuable races automatically carry weight penalties which are added to a horse's Grand National weight.
Even if a horse is allotted a weight of 8st 12lbs, it must carry 10 stone as this is the required minimum.
This means some horses will be carrying possibly a stone more than they should be (known as being out of the handicap) and this disadvantage should suggest they are likely to perform less well than their rivals.
A modern-day record of 92 horses were originally in the handicap proper in 2005 with that number dropping to 85 in 2006. However, a maximum of 40 will line up on the day.
Many punters will automatically put a line through horses out of the handicap.