Ki Clones (気の分身 Ki no Bunshin) is a technique used by Hit.
When moving around, Hit is able to leave duplicates of his ki, in order to make it hard to track him. He uses this to get behind an opponent while they are distracted thinking he is elsewhere. Hit can create this with his Tides of Time. Goku trained his sensing capabilities for an entire day prior to fighting Hit to be able to tell when he'd appear but Hit's ki duplicates could still fool Goku and let him easily sneak up behind him after. When the fight changed locations to a forest and Goku closed his eyes and focused his sensing to amp it he still took a minute or more to be able to sift through thousands of ki duplicates to find the real Hit.