In what may serve as a harbinger to year-round harness racing, Rosecroft Raceway goes into its fourth decade with the earliest opening of its 30-year history tonight. The 85-night meet, extending through June 16, will severely test both the handicapping skill and money-managing ability of the most dedicated aficionado.

The past several seasons have afforded me an intimate view of the handicapping problems confronted by the average racegoer. Conversations with numerous fans have led me to conclude that their greatest frustration is attributabel to a lack of understanding regarding the manner in which pacing and trotting races are contested.

Before examining the often puzzling aspects of final and fractional times, parkouts, driver, class, current form and dozens of related handicapping factors, the bettor should have an understanding of how races are contested and the manner in which the pace of a given race may have affected the performance of each competing horse.

Since most races group horses which are nearly equal in ability, final clocking, when considered by itself, becomes relatively meaningless. A race featuring a horse inherently several seconds faster than its competitors requires no handicapping skill. The animal's superiority will be obvious to all and invariably will produce a mutuel too small to whet the appetite of the casual fan.

The single most important factor in rating harness races over a half-mile track (such as Rosecroft) is the manner in which the race most probably will be run. Early position, or how the field is most apt to be aligned after a quarter-mile, takes precedence over all other handicapping factors.

The importance of early position is sharply brought into focus when one realizes that over the past three years 81 percent of all races at Rosecroft have been won by horses which were no further back than fourth after the field had raced a quarter-mile.

It may surprise most fans that 35 percent of Rosecroft's winners over the same period held the lead by the quarter. In addition, 19 percent of the ultimate winners were second at the quarter, while 15 percent were third and 12 percent were fourth at the quarter. Clearly, if a horse is unable to reach a prominent early position, its chances of victory are greatly reduced.

The initial decision confronting the race analyst is a determination of the manner in which the race is most likely to be contested. Are the racing characteristics of the competing horses most apt to bring about early speed, or are they likely to bring about a slower pace?

From a handicapping standpoint it is important to divide the race into halves. If the first half-mile is expected to be slower than the second, it will decidedly favor those horses racing in a forward position. In other words, if the pace-setting horses are allowed to set moderate early fractions, normally they will have conserved suficient energy to withstand the late challenges presented by the trailing horses.

However, if the first half-mile is expected to be faster than the second, it is unlikely the front-runners will have retained sufficient energy to repel the closing bids of the comparatively fresh "come-from-behind" horses.

The number of early speed horses. their relative post positions and the type of speed is vital in determining the manner in which a race is most likely to develop.

The value of early speed is largely negated if the horse cannot be rated once it has reached the lead, or a prominent forward position. Many harness horses are referred to as "pullers." This means they are headstrong and refuse to be driven in an energy-conserving manner. They simply will travel as far as they can as quickly as they are able. In the process they will burn up energy and oxyan at an accelerated rate. This type of horse generally tires and shortens stride very abruptly

There are also many horses which refuse to race "in a hole" (between horses aligned alongside the rail). Rather than allow themselves to be comfortably rated, behind another horse, they will insist upon coming out toward the center of the track and engage themselves in an energy-sapping duel for the lead.

There are, however, many horses which may be called upon to expend energy in a quick burst for early position and then will permit themselves to be rated while conserving energy for the stretch drive. Animals of this nature are those which most often present a bettable situation.

Favorable wagering situations most often materialize when (1) a rateable early speed horse has an inside post and ooes not figure to be seriously threatened for the early lead, and when (2) a strong closer, with moderate early speed, has an inside post while two or more early speed horses have outside post positions.

The foregoing is obviously an over-simplification, in the interest of brevity.

The point to be made is the importance, to the handicapper, of developing a solid foundation for predetermining the manner in which a race is most apt to be run, and how the pace can effect the outcome. The observer then is more competent to watch a race and objectively analyze its subsequent outcome.

As the understanding of how races are run becomes increasingly acute, the fan also becomes increasingly aware of the numerous situations that often develop to prevent the best horse from winning a given race. What may appear to have been a nondescript performance, as presented on the program, may instead have been an excellent race in which a horse was prevented from a closer finish by any one of a number of possible circumstances.

The horse may have been forced three of four wide around a turn; it may have been trapped behind a tiring horse; it may have become involved in an energy-consuming duel for position, or the driver may have been forced into a premature move. The program is unable to present this information.

With this broader understanding, and knowledge of how pace often dictates driver strategy, will come the ability to watch races in a more objective manner. For it is in the watching of races that one will reap the rewards of longshot winners.

The driver is of great importance in handicapping. It does little good to preanalyze a race well if the driver is not sufficiently skilled to best take advantage of the potential situation.

Space does not permit the listing of the habits, patterns and idiosyncrasies of all the local drivers. However, I feel these are the best:

1 -- Robert Myers, 2 -- Wayne Smullin, 3 -- Walter Callahan, 4 -- Hurbert Jackson, 5 -- Bib Roberts, 6 -- Presley Moore, 7 -- David Banks, 8 -- Carlton Williams (underrated), 9 -- Richard Kent, 10 -- Walter Layfield, 11 -- Stephen Guy, 12 -- Jim Porter, 13 -- John Childress and 14 -- Jim Brittingham. On the distaff side Young Linn Truitt may be a budding star. In addition, a rapidly improving John Wagner may well enter the top 10 this season.