There are many good reasons for being grateful to the Greek National Theater for its version of the great tragedy by Sophocles, ''Oedipus Rex,'' which it will be performing through Sunday at the Lincoln Center's Vivian Beaumont Theater. But reservations are also prompted about whether this highly rhetorical play was the best choice to send to a country where Greek is not widely understood.
Cause for gratitude arises not only from the exportation of a play that is one of the constant beacons in mankind's often blurred study of itself but also from a staging that has the sight and feel of an authentic work in its native habitat. Sitting in the Beaumont's amphitheater seats, the sense of being in the audience at an ancient amphitheater is created by the impressively spare and tilted stage. The players are clad in robes and masks that contribute a diversity and color sorely needed in this merciless, hard story.
Minos Volanakis, the director, has virtually choreographed the chorus, reversing its traditional static stance so that it now acts as conduit for the story not only in words but also in theatrical exercises that have its members standing, kneeling, snaking about the set, sometimes doffing their austere robes to show that the chorus, too, is composed of mere men.
Despite its visual attractions, language, in this case, creates a formidable barrier between audience and performance. Many in Tuesday's opening night audience, representing the elite of New York's Greek community, understood this modern Greek translation by Mr. Volanakis from the virtually unintelligible ancient Greek. Some of them could appreciate the subtle use of terms common in Greek Christian liturgy inserted into a script about pagan gods. But for those who didn't, the house was simply too dimly lit - aptly for this stark tragedy - for one to follow the synopses that tell of each scene in the one-act play during its 100-minute course.
''Oedipus Rex'' is a tragedy told in words, not in events onstage. It is a whodunit in which the chief investigator, King Oedipus of Thebes, searches for the criminal who has upset the gods by sinning, only to learn that the criminal is himself - that he had unwittingly fulfilled a prophecy and killed his father, the former king, and married the widow, his own mother. Here is fate so cruel it even makes the pure at heart demonstrably guilty.
It's hard enough to get this across in one's own language and virtually impossible to do when spoken in another tongue. Nikos Kourkoulos, in the title role, is a powerful and handsome performer with a strong delivery, but one suspects that there are cultural differences in how this role would be interpreted in English-speaking theater - perhaps with more modulations of voice, allowing for introspective lows and the manly assertive highs. Nikos Kavvadas, as Kreon, the brother-in-law falsely accused of disloyalty, and Katerina Helmi, as Jocaste, the mother-wife, come across similarly, clear but not particularly moving in their portrayals. G. Danis as Tiresias, however, does inject passion as a gnarled and wizened holy man, bent at right angles, his voice crackling and snarling with an anger born of knowledge that he knows cannot affect events.
Although some may be interested in seeing imaginative stagecraft from a country where theater was born, others, less venturesome and curious, may find ''Oedipus Rex'' something of a chore. That is what prompts the wish that this talented ensemble might have brought us something that might better vault barriers of vocabulary by appealing more to the eye than to the ear, to the heart than to the brain.