Henry Cowell's 'Mosaic Quartet' and 'Ongaku'

Mosaic Quartet was Henry Cowell Third String Quartet and, whilst not specifically Eastern sounding, is an important American work because it employed a quite loose and somewhat revolutionary open form, which could perhaps be dubbed ”aleatory structure” or "free form". 

Composed in 1935 and described as a “crazy quilt of 5 patterns”, the self-contained mosaics are performed quite literally "in any desired order," as per the composer’s instructions,  As in the strophic structure of a hymn, this mosaic divides into two halves; each verse is five phrases long not the perhaps expected four phrases, and the harmonies are noticeably dissonant, with the exception of straight-out majors (at the beginning, middle, and coda). The four other mosaics are miniature texture studies.  Thus no two performances will sound the same, a notable innovation for the mid 1930s.

Cowell's ONGAKU, on the other hand, is one of his most Eastern-inspired works and an important (late) orchestral work of the composer.  He wrote the following description of it:

"I write as a Westerner, for Western orchestras, but my Ongaku is music in which I have allowed myself to be influenced by the sunny splendor of Japanese music, as other Americans have subjected themselves to the influence of German, French, or Italian traditions.

The foreign music strangest to Western is certainly that of the Far East; China, Korea and Japan. But the strangeness to me seems largely superficial, a matter of tone color and performing technique rather than musical structure. That the music of the East and West are related is attested, I think, by the fact that Western orchestra performers will find nothing particularly surprising in their individual instrument parts for Ongaku (except for the overblown technique for the flute), in spite of the unfamiliar general style in which the music is couched.

Ongaku is in two movements, the first very slow and stately, related to the ceremonial Gagaku music of the Japanese court. The second movement is somewhat faster, lyrical but precise, and it owes something to a more recent style of Japanese ensemble music called Sankyoku"