Monday's concert ranged from very fine to revelatory.

Of particular interest was the presence of the Tokyo String Quartet, which was making its Chamber Music Northwest debut at the outset of the final year of its distinguished career. Among the world's most venerable chamber ensembles, the quartet formed in 1969 at The Juilliard School, its members previously having studied together at Tokyo's Toho Gakuen School of Music. Last year, two of its members -- founding violist Kazuhide Isomura and violinist Kikuei Ikeda, who joined in 1974 -- announced their retirement; violinist Martin Beaver and cellist Clive Greensmith had originally planned to replace them, but in April they conceded the insurmountable difficulty of rebuilding the ensemble without its two longest-serving players, and in April the quartet announced that 2012-2013 would be its last season.

If the intention was to quit while strong, and not after fading, as its contemporary the Guarneri did before retiring in 2009, the timing was right: they've still got it. Armed with a set of Stradivarius instruments formerly owned by Niccolo Paganini, they created rich, resonant sounds with exquisite balance, from Beaver's bright, focused violin to Greensmith's firm but buoyant cello. In the Debussy, the high point of the evening, vivid colors came and went through smoothly flowing harmonies, and the quartet sounded unforced even in the most animated passages. The third-movement Andantino, especially its muted outer sections, was a display of spellbinding sonic beauty. With oboist Stephen Taylor (in place of Ikeda) leading with lovely cantabile playing, the Mozart unfolded with ease and elegance.

The Tokyo's imminent departure from the world stage lent poignance to the finale, the Mendelssohn Octet, as they were joined by the Amphion Quartet, which has returned for a second year to participate in CMNW's Protégé Project, an initiative to spur the careers of a new generation of chamber musicians. Here were two quartets, one near the end of its run and the other near the beginning, in vigorous collaboration in music by a 16-year-old emulating his great elder, Beethoven. And so the torch is passed.