An electromechanical locking system includes a locking mechanism that is switchable between a locked position and an unlocked position, a keyway for receiving a rotatable key, a latch, and an angle detector for detecting an angular orientation of the key while the key is in the keyway. After detecting a sequence of angular orientations of a key, the angle detector may issue a corresponding angle sequence data. A lock controller controls the latch in accordance with an authentication data that has been received from the key and the issued angle sequence data that reflects a combination code. If the authentication data and the angle sequence data are both valid, the lock controller enable operation of the latch, whether automatically or manually. The key includes a light source that projects a light beam at an acute angle in order to provide a visual indication of a current angular orientation of the key.