In The Mozart Companion (Faber: 1956), Hans Keller dismisses the early string quartets as ''on the whole abominable''. ''Why play them at all,'' he asks, ''and insult Mozart's genius?'' Well, a glance at the current Classical Catalogue reveals that only the Amadeus (DG—1/89) and the Quartetto Italiano (Philips—8/87, recently reissued as part of the Complete Mozart Edition) have seriously risked insulting Mozart's genius by recording the early quartets in toto; and if you want their performances you have to buy all of Mozart's later quartets as well. So for those Mozartians who already have one or more versions of the ten great quartets and want to test Keller's denunciation against their own experience of the music, this new set of the early works by the brilliant young Hagen Quartet fills an obvious niche.
Though there's some stiff and self-conscious writing in these early works, and in places an evident technical immaturity (something one rarely feels with Mozart's contemporary orchestral works), I doubt whether many listeners will feel that this music is anything like as atrocious as Keller affirms. Three of the works here are, of course, well-known: the fluent, ebulliently Italianate divertimentos, K136-8, usually performed with orchestral strings, though even more effective when played one-to-a-part, as the composer almost certainly intended. The very first quartet, K80, written when Mozart was 14, is also a fluent, unpretentious piece, though, like K136-8, it is violin-dominated throughout, with little real four-part discourse. With the six works composed in Milan during the winter of 1772-3, Mozart's quartet writing begins in earnest. I can't say I found my attention riveted by K155, which in places had me sympathizing with Keller, but each of the other five quartets has at least one compelling movement. Perhaps the most accomplished of all is K156 in G, which even escapes Keller's censure: there is a witty development (with some genuine quartet textures) in the breezy, waltz-like opening movement and an E minor Adagio of surprising intensity. Other striking minor-keyed middle movements in this set include a melancholy, chromatic serenade in K157—a fine, elegantly wrought work—and a stern, angular G minor Allegro in the otherwise dull (and sometimes awkwardly written) K159.
If the Milanese quartets hover between a lightweight divertimento style and a more serious, 'learned' manner, the six quartets Mozart wrote in Vienna in the late summer of 1773 are notably more intricate in texture and thematic working, with contrapuntal writing likely to crop up in almost any movement. Mozart had recently got to know Haydn's three latest sets, Opp. 9, 17 and 20; and quite often we can sense the young composer struggling to assimilate the older man's powerful influence. Several movements have direct Haydn models, including the Andante of K168 (a fugato based on the same tag as the finale of Op. 20 No. 5) and the minuet of K173, which quotes from the corresponding movement of Op. 9 No. 4. And taking their cue from Haydn's Op. 20, two of Mozart's finales are purely fugal, with that in K168 apparently modelled on the skittish fugue in Op. 20 No. 6. I won't be rushing to play either K169 or K170 again (the latter, according to Keller, ''has little musical value and shows multiple defects''—an exaggeration perhaps, but not by much); and only the sensuous Adagio (faint premonitions of ''Porgi, amor'' in Figaro here) would lure me back to K172. But K168, for all its conscious polyphonic display, is often impressive as, in its slightly less studied way, is K171, with its recurring Adagio introduction and spiky, neo-baroque C minor Andante. Finally there is K173, Mozart's first sonata work in the minor, lacerated by Keller (''packed with cliches and topped by a dreadful fugue...''); but in the first movement and minuet, at least, Mozart seems to me to handle the conventional minor-keyed language of Sturm und Drang with a certain individuality, creating music of edgy chromatic intensity and some structural subtlety.
If you prefer the sparer, leaner sonorities of early instruments in this music, the Hagen may strike you as too rich-toned and sophisticated. But for most listeners, I suspect, their polished, supple, vividly etched playing will be near-ideal. Intonation, ensemble and internal blend are almost faultless, in the Alban Berg class: time and again in these works the two violins play either in thirds and sixths or in octaves, and invariably I was struck by the uncanny precision and unanimity of playing. But technical finish is never an end in itself. The Hagen bring a decisive character and sense of commitment to each of these quartets: listen to their grave, hushed opening of K173, where their use of minimal vibrato heightens the music's austerity; or, at the other end of the spectrum, the flair and elan of their playing in the virtuosic outer movements of K136. Perhaps Mozart would have been surprised at the emotional weight the Hagen bring to some of the slow movements, especially the Adagio of K156, where they make much of the dissonant appoggiaturas and sudden dynamic contrasts. But their intensity never sounds contrived or overblown to me; and the composer would surely have appreciated the leader's pure, sustained line in such movements as the opening of K80 and the Un poco adagio of K170. My only, slight, quibbles are that one or two fast movements seem a shade over-driven (the finale of K160, for instance) and that there is an occasional hint of hurrying elsewhere, as in the main theme of K169's finale.
Unless you feel that modern instruments simply have no business tackling this repertoire, you'll be lucky to hear better performances than these vital, resourceful and beautifully recorded readings. Though Hans Keller would probably have remained unrepentant even in the face of the Hagen's advocacy, many listeners will find unsuspected pleasures in these uneven but intriguing works, and at the same time learn quite a lot about Mozart's creative development.'