This paper describes a novel image-based geometric registration method using visually elegant and robust semi-fiducial markers in mixed reality (MR). Most traditional visual markers stand out against the background, i.e., they can be recognized and identified easily. Here, we try to construct new visual markers for MR registration, which achieve a good balance between visual elegance and robustness. As the first step, we propose “two-tone colored markers”. These markers have the following characteristics: 1) color similar to that of the background object, 2) placed at the corners of real objects in an inconspicuous manner. This paper describes the registration method using twotone colored markers and a few experiments. CR Categories: H.5.1 [Multimedia Information Systems]: Artificial, augmented, and virtual realities―