Introduced during the Whole Cake Island arc, Future Sight is an extension of Observation Haki, which allows users to predict what someone is going to do, usually seconds prior, in what resembles a pseudo-form of precognition.
Shanks without a doubt is the best user of the Future Sight Observation Haki so far: during a confrontation with Yonko Shanks, Kid prepared to unleash his most powerful attack, Damned Punk. His plan was to obliterate all nine of Shanks’ allied ships, wiping out everyone on board in a single devastating strike. Kid confidently declared that he would accomplish this feat within 10 seconds. However, before Kid could launch his assault, Shanks activated his Future Sight Observation Haki. In those crucial moments, Shanks glimpsed the entire future—spanning over 10 seconds—in his mind. He witnessed Kid successfully destroying each of the ally ships and even eliminating their captains.
Shanks recognized the severity of the situation and swiftly intervened to prevent Kid from harming his allies.
Shanks’ mastery of Future Sight Observation Haki stood out—effortlessly allowing him to foresee events up to 10 seconds ahead. It’s quite possible that his abilities extend even further beyond that!