Bela Bartok once said, "Competition is for horses, not artists." With the Kentucky Derby only 12 days away, no one is likely to argue with the first half of that didactcism. But the 12 pianists who played in the final sessions of the Friday Morning Music Club's International Competition eight days ago might have a very different view of the concluding half.

So, too, might Ann Schein, David Burge and Robert Goldsand. They were the judges who gave a fascinating demonstration - in a dozen hours of concentrated listening, comparing and eventual selecting - of the fine art of judging.

Cash prizes plus bonuses rewarded artists long before Richard Wagner's Veit Pogner (in "Die Meistersinger") gave his entire fortune plus his daughter, Eva, to Walther von Stolzing, the best young singer to come down the Nuremberg pike. Judges' decisions in hundreds of contests now determine who will get the more than half-million dollars in prizes each year.

Last Friday and Saturday the judging team of Schein, Burge and Goldsand helped the music club dispense $4,525 to the six pianists whom they had chosen the previous day out of the semi-final field of 12.

Money is far from the only prize the young artists win. Among the avenues that can be opened to lucky winners are public appearances - solo and orchestral - contracts with leading managements, opportunities to conduct major orchestras, and, for a lucky few, the possibility that recording companies will seek them out.

The decisions of judges often, perhaps always, seem strange to those who do not win top prizes. The questions that plague those who come in second, third and fourth must be the same who listen so intently to preliminary and final rounds. (Last fall in Fort Worth, the audience was so angered at the judges' choice for the first prize of $10,000 that some of them got together and raised an equal amount, which they presented to the pianist of their choice.)

What was there about No. 7's Chopin Impromptu that the judges liked better than No. 11's? Or how will these particular judges react to the pianist who pours out a torrent of glittering pianism in "Islamey" by Balakirev, in comparison to the pianist who offers a reading of the Brahms-Handel Variations that is superb in mature perspectives, as well as in magnificent playing?

Last week's music-club jury was a remarkable balance of judicial temperaments. Schein's playing has always combined musical insights with a keen technical prowess and a welcome emotional thrust. Goldsand has been known to musicians for years as a master of classical style as well as in the distinction of his Debussy, Ravel and other 20th-century masters. Burge's name is among the most acclaimed today for his extraordinary command of the most advanced piano writings of the past half century. He also headsf the piano department of the Eastman School of Music, and his authority in all branches of piano literature is complete.

Time after time the three judges stressed their interest in much more than sheer technical bravura. Equally clear was their search for the pianist-musician whose foremost concern was for the making of music through the medium of the piano. This process was illustrated by the particular pieces the judges asked each competitor to play.

Each was allowed to begin his allotted time with a work of his own choice. Those choices reflected many things: What the contestants felt most comfortable with at a time when nerves are likely to be stretched their tightest; what they might think showed them off best right off the bat; what they may have thought the judges would most like to hear at that particular moment. Thus one pianist began with a Rachmaninov Etude-Tableau, while another preferred to begin with a Bach Prelude.

In nearly every case, the judges proceeded by asking for music in complete constrast to whatever was played first. Thus the pianist who began with "Islamey," a piece that still holds its reputation as one of the real toughies, was asked to follow it with the B Flat Prelude and Fugue from the Second Book of Bach's Well-Tempered Clavier. This switch in mood and style is, incidentally, one no pianist would dream of deliberately programming.

But in these competitions, all things must be held possible. What showed up in the Bach was that the elusive quality called "musicianship," which is irrelevant in the Balakirev, but is of great importance in bach, was noticeably absent. Perhaps to check this element still further, the judges next asked for the last movement of the Mozart Sonato in D, K. 576, before calling for the Scriabin Nocturne in D Flat, for the left hand alone. In any case, the Mozart, while clean as a whistle, had unstylistic retards that disturbed its natural line. By contrast, the Scriabin was a dream in tone and total technical assurance.

The judges' deliberations were quite properly not made public; only their decisions. But a generous side of their approach to their difficult task showed up Friday afternoon when they took the time to talk individually with each of the six who had just been eliminated. It is in such private sessions, which are by no means common, that young contestants, going through the agonies of nerves and months of preparing the required repertoires (which often vary widely from one competition to the next) can gain invaluable advice from the experts who have, frequently after painful deliberations, made their final decisions.

Robert McDonald, whose musical authority was a solid as his resounding command of his instrument, emerged in first place, the only winner whose prize was not divided by the judges. In addition to his prize of $2,000, he will play a recital in the Phillips Collection next Jan. 28, giving the Washington public a chance to hear the brand of playing so highly esteemed by the trio ofjudges.