What is the name of the early phase of Cubism from 1909 to 1912?

The early phase of Cubism from 1909 to 1912 is called Analytic Cubism.

Analytic Cubism broke subjects into overlapping, faceted planes so that an object could be suggested from several viewpoints at once. Pablo Picasso and Georges Braque usually worked with restrained browns, grays, greens, and ochres, making structure more important than bright color or easily readable detail.

The phase grew out of their experiments after 1907 and reached a particularly influential form between 1910 and 1912. Still lifes, musical instruments, bottles, newspapers, and portraits were common subjects because familiar objects allowed viewers to reconstruct the fractured image. The term “analytic” refers to this visual process of taking forms apart and examining their components.

Analytic Cubism is commonly contrasted with Synthetic Cubism, which followed from about 1912 and used simpler shapes, stronger colors, and collage materials such as newspaper and patterned paper. “Proto-Cubism” generally describes earlier transitional experiments, including Picasso’s 1907 Les Demoiselles d’Avignon, rather than this 1909–1912 phase.