Orientations of Ro(max) and Ro(min) of vitrinite have been determined in coal samples that have been deformed in simple shear experiments at T = 650 degrees-900 degrees C, confining pressures of 0.8 and 1.0 GPa and constant displacement rates of 10(-5)-10(-6) s(-1). Samples chosen are a high-volatile bituminous coal and two anthracites. Shear strains up to 3.0 were attained in experiments that lasted up to 100 h. High temperature and large strains have facilitated an increase in Ro(max), an increase in anisotropy (bireflectance), and reorientation of Ro(max) and Ro(min). Results of these experiments indicate that tectonic strain, at and above semi-anthracite rank, enhances the degree of molecular ordering leading to preferential growth of graphite and that vitrinite anisotropy may track with tectonic strain.