The Peeping Tom is usually privy to the most intimate affairs. And for the music-loving Peeping Tom, the delights of chamber music are inexhaustiable, as the Tokyo String Quartet revealed last night at the Corcoran Gallery.

Opening the concert season at the Corcoran, the Tokyo Quartet provided aural pleasures that ranged from expressive sweetness and wild abandon to bewitching broodiness in a program made up of works by Schubert, Beethoven and Claude Debussy.

Debussy's only essay in the quartet came across under the Tokyo not as opaque and misty, but as sharp and clear in line and dynamic nuance as a steel engraving. How musically, for instance, the Tokyo coped with the variations in tempo in the first movement. How attentive they were to Debussy's direction of "doucement (gently, smoothly) expressif" in the Andante. How airy and clean were the pizzicati in the second movement marked "assez vif."

Changing gears into Debussy was no problem for the Tokyo after Schbert and Beethoven -- here is a wellgreased transmission. Yet one could have wished for more refinement and less calculation in Schubert's youthful Quartet in E Flat, Op. 125, No. 1, and fewer heavy accents and more subtle sobriety in Beethoven's "Quartetto Serioso."