Twenty-nine-year-old Pi-Hsien-Chen won the International Johann Sebastian Bach Piano Competitions yesterday afternoon at Lisner Auditorium. Established in 1959, the Bach competition is the closest that Washington has to compare with Moscow's Tchaikovsky competition for Fort Worth's Cliburn. Over the last decade, it has been become a musical event of international importance.

For the finals of this stiff and stringent contest the judges selected Bach's treacherous Goldberg Variations, which the three finalists played consecutively. Chen played third, and there was no question by the end of her recital that she was the audience favorite.

Bach composed his "Aria with Diverse Variations for Clavicembalo" to be played by Theophilus Goldberg, the house musician of the wealthy Count Hermann Carl von Keyserling. They were intended to help cure the rich man's insommia, and it takes a brilliant and lively pianist indeed to keep them from fulfilling their original intentions. With Pi-Hsien-Chen's musicality and passion, they emerged as the epic masterpiece that they constitute: a compendium of the musical feelings of an age, with presages of the power to come.

It was hardly a display of technical perfection. Her touch was arguably anachronistic from the beginning, but also decidedly alive. Hers was a very personal approach to this long work, at first bringing out all the dance of the fourth and seventh variations. In a masterpiece in which the tonal foundation seldom varies -- only three episodes in the minor key occur -- much depends on the daring of the pianist, and the bravura of Chen's playing became captivating in the French flavor of the Maestoso movement that opens the second half. She took full advantae of the chromaticism of the Adagio in G minor at No. 25, and her piano was on fire through the glorious variation No. 28, in which Bach anticipated the strength of an entire future of music. Chen paused longer than her colleagues between variations, collecting herself each time and making the G major aria return at the close with all the heroic sweetness of an old love.

The audience cheered their winner, and the judges followed suit. Emerging from behind a screen that had concealed them from the contestants, Gaby Casadesus, George Walker and Gerhardt Puchelt presented the pianist with awards amounting to $6,250. Chen, a German citizen, studied at the Hochschule fur Musik in Hanover. She will be appearing next season in concert with the Baltimore and National Symphony Orchestras, performances that no lover of music will want to miss.