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We present a technique for detecting gestures on the edge of an unmodified smartwatch. We demonstrate two exemplary gestures, i) Sidetap -- tapping on any side and ii) Slingshot -- pressing on the edge and then releasing quickly. Our technique is lightweight, as it relies on measuring the data from the internal Inertial measurement unit (IMU) only. With these two gestures, we expand the input expressiveness of a smartwatch, allowing users to use intuitive gestures with natural tactile feedback, e.g., for the rapid navigation of a long list of items with a tap, or act as shortcut commands to launch applications. It can also allow for eyes-free interaction or subtle interaction where visual attention is not available.