This is a fundamental variation of the full snatch exercise. The main difference between this variation and the full snatch is the height in which the bar is received in the catch.
Start in the snatch position from the floor. With your feet hip width apart, turn your toes open 15-30 degrees. Grab the bar with your hook grip, and load yourself into your snatch pulling position. As you ascend, pull your knees back shifting the weight from the balls of your feet to your heels, all while staying over the barbell with the chest and lats. As you pass the knees, explosively bring the bar vertical up the legs and extend your hips, transitioning into your high pull. Quickly reflex your hips and knees, rotate the barbell to "snap yourself under the bar", forcefully extending the elbows and driving yourself under that bar. Your end catch position should have the bar locked out overhead, with your hips at or above parallel.
This is a fundamental snatch variation to build overall strength and power in the movement. By limiting the full catch position, you force maximal power and upper body strength, hip extension, and enhanced turnover of the barbell in the catch.
Typically, repetitions are kept in the 2-5 range with a load that is 60-80% of maximum.