The initial yield stress of the material in tension is A. If the same ductile material were tested in compression, the yield strength would be approximately the same, point B on the dashed curve. Now, consider that a new specimen is loaded in tension past the tensile yield stress to C along the path O-A-C. If the specimen is then unloaded, it will follow the path C-D, small elastic-hysteresis effects being neglected. If now a compressive stress is applied, plastic flow will begin at the stress corresponding to point E, which is appreciably lower than the original compressive yield stress of the material. While the yield stress in tension was increased by strain hardening from A to C, the yield stress in compression was decreased. This is the Bauschinger effect. The phenomenon is reversible, for had the specimen originally been stressed plastically in compression, the yield stress in tension would have been decreased. One way of describing the amount of Bauschinger effect is by the Bauschinger effect β. This is the difference in strain between the tension and compression curves at a given stress.