Just one block from the White House, the director of the Corcoran Gallery welcomed last night's audience to the Tokyo String Quartet concert with numerous references to the unusual week in progress in Washington. He said something about the quartet having rehearsed in an office or a closet because of the special events taking place in the gallery.

But from the program they played, you would think they were involved in a celebration for a new president of West Germany or Austria. There was the Quartetsatz by Franz Schubert, the Five Pieces by Anton Webern, the early G Major Quartet by Ludwig Beethoven, and the C Minor Quartet by Johannes Brahms.

No one would guess from the concerts at the Corcoran that any American composer had ever had enough wit or wisdom, skill or imagination to write a string quartet. And this is as good a time as any to suggest that the situation is long overdue for a radical change.

The four men in the Tokyo Quartet play like a dream. Their tone is silky, their intonation secure, their style admirable. If they need a list of quartets by Americans, one could be provided. There is even a legend that Benjamin Franklin wrote one. Wouldn't that have been a treat last night? It is long past time the Corcoran indoor concerts matched the Corcoran's great outdoor Americana.