Nagashi uke (literally: “sweeping-hand block”), the sweeping block is not a block per se; it allows a karateka to forego their chance to block in exchange for a speed bonus on an outside 7-3. Be aware that this technique compromises the defense-in-depth that comes from combining blocks and evasions. For this reason, sweeping blocks are reserved for advanced students, who should have a high degree of skill and confidence with evasions.
Enter a same-side front or fighting stance, and extend your same-side arm in front of you, parallel to the floor. Hook your hand behind your opponent’s same side shoulder, then 7-3 to the outside, while simultaneously pulling your hand to your opposite-side shoulder.
[sweeping hand block in the air from the front and the side, fast and slow.]
As you step past your opponent to the outside, you will simultaneously pull your opponent towards you and to the inside, augmenting your 7-3 in all regards.
This is a dynamic move, and it makes little sense to practice alone in the air. It is best to practice this with a live partner, or if one is unavailable, you could use a tree, post, column, etc.
[sweeping hand block from the front and the side, fast and slow, against a partner and against a post]