Abstract: An improved tape cassette containing markings on the edge of the tape which contrast with the color of the tape. When the tape edges form the tape reel face as the tape is wound on one hub of the cassette an easily seen pattern is formed. This pattern is readily visible even under poor conditions of visibility through the cassette window. During recorder/playback use the operator can quickly check to see if the tape is moving by noting the pattern movement when viewed in the window.