Mozart, Bartók, Kodály, and Ravel wrote great string duo works. But composer Leclair (himself a violin virtuoso) conveyed more effortlessly that, on his own terms, two violins can be a complete entity.
Although Leclair lived at the end of the French baroque, his Sonata for Two Violins in D major (Op. 3 No. 6) looks forward to more Mozartean times, written with a combined charm and technical command of the instrument suggesting that more than two instruments are onstage. His invention was such that you wondered why this music isn't played all the time. One possible reason: With only two instruments, intonation has to be airtight - mostly the case here, though lapses were more audible than you'd expect.
Leclair wasn't the concert's primary discovery. Milhaud's early-period Sonata for Two Violins and Piano (Zhu included) couldn't be more delicious, with Debussy and Ravel echoes fused with the composer's cabaret sensibility.
After intermission, Kang played Capriccio for Solo Violin by Joaquín Rodrigo, known mostly for guitar concertos - but this 1944 work seems to have been written as a neck-and-neck race with Bartók's contemporaneous Sonata for Solo Violin. Rodrigo's piece is dazzlingly dense, full of many technical tricks one would expect, but also a kind of Iberian delirium that Kang heartily tapped into.
In such company, Prokofiev's well-known Sonata for Two Violins, the program's best-known piece, was outclassed, and maybe in the minds of the performers as well: More complicated textures could have been cleaner in Kim/Kang's performance.
What was Kreisler's lovely, soulful Liebesleid doing in such company? I don't know, but Kim's performance was ingratiatingly Viennese, as if speaking the music as a first language. Sarasate's Navarra for Two Violins and Piano was mainly a fireworks piece, but written with the two violinists behaving like mirror images until, first subtly and then dramatically, they went their own ways.