The snatch grip deadlift is variation of the deadlift that places more focus on the upper back as well as mobility
With your snatch grip pull yourself into your starting position (make sure you can achieve a straight back before lifting. If not then you need to work on mobility). Shoulders should be slightly ahead of the bar, weight to the front of the foot and bar pulled back into the shins. To initiate the lift, take a breath in and engage everything in the trunk. Keep tension throughout. Push hard into the floor with your legs, the weight should slightly back towards the heels as the bar leaves the floor. The same back angle should be maintained until the bar reaches mid thigh with a focus of keeping the chest up. At this point, finish the lift by fully engaging the glutes and quads and extending at the hip and knee until in an upright position and arms at full length. On completion of the lift the shoulders should be slightly behind the bar with the weight firmly through the heels and the abs engaged. Reverse the movement and control the bar back to the floor for the next lift.
The snatch grip deadlift is a great strength builder for the posterior chain as well as the trunk. Due to the increased range of motion more emphasis is placed on the legs, upper back and grip (when not using straps).
Generally speaking reps of 1-6 are most commonly used, depending on phase of the program. If being used to strengthen posture and positions in the snatch then the weight used should not exceed that of which proper form can maintained.