Minecraft wiki entry for Sword, associated text: If the attack recharge meter is 84.8% or above, and the player is standing or moving no faster than walking speed, the sword performs a "sweeping" attack that hits nearby enemies for 1 and knocks them back. All enemies within 1 block horizontally and 0.25 blocks vertically of any part of the attacked mob and whose feet are less than 3 blocks away from player's feet are affected. The Sweeping Edge enchantment increases the damage dealt by 50% of the normal hit damage for level I, 67% for level II, and 75% for level III. The amount of knockback is 80% that of the knockback due to Knockback I (in other words, 2.8 blocks), and does not benefit from that enchantment. It is impossible to perform a sweep attack at the same time as a critical hit or sprint-knockback attack or while riding something.