The ninth Young Concert Artists Series at the Kennedy Center got under way yesterday at the Terrace Theater with a fine recital by pianist Hung-Kuan Chen. A native of the Republic of China on Taiwan, Chen delivered an ambitious debut program designed to test the mettle of even the most seasoned artist.

Beethoven's monumental Sonata, No. 29, in B-flat major, Op. 106 (the "Hammerklavier"), filled the concert's last half with musical certainty and technical freedom. Chen gave a provocative reading of the heavenly adagio, sensitive to all aspects of the music's huge proportions. The grand fugue of the finale began with brilliant energy and elasticity and showed the pianist's strength of tone and finger work.

His playing of Chopin's Sonata in B-flat minor was equally mature. Yet some passages (the right-hand line of the first movement and the scherzo's songlike middle section, for example) acquired a brittle quality that distracted from the otherwise attractive tone and shape.

The luscious wave motion of Ravel's "Ondine" from "Gaspard de la Nuit" was presented with utter spontaneity and clear, flexible phrasing. Here Chen's pedaling was particularly impressive. Scriabin's ever-changing Sonata No. 5, Op. 53, a vast and varied palette of tonal colors, meters and rhythms, was attacked with fire. Chen molded the many moods into an emotionally rich and technically excellent performance.