Next week, when V.I.P.s and special guests shuffle through Christie’s new West Galleries, in Rockefeller Center, they will alight on a series of abstract paintings by a group of relatively unknown artists. These pieces reflect a recent market craze for attractive, anodyne work with an emphasis on process and materials. But the artists at the West Galleries are not young painters from Brooklyn, Berlin, or Los Angeles. They are a group of Korean octogenarians who comprise a movement known as Tansaekhwa (or “Dansaekhwa”) and have been producing in this style since the nineteen-seventies.