During the Warring States period, a man from the state of Chu was crossing a river by boat. As the vessel reached the middle of the river, the precious sword he had been carrying slipped from his hand and plunged with a splash into the swift, turbulent waters. Everyone on board grew anxious for him, urging him to jump into the water immediately to retrieve the sword or at least fetch some tools to help. But the man from Chu remained utterly calm. He pulled out a small knife, carefully etched a distinct mark onto the side of the boat where the sword had fallen, then turned to the crowd and said, “Don’t worry—my sword fell right here. Once the boat docks, I’ll follow this mark down into the water and retrieve it.” The onlookers shook their heads in disbelief, but the man from Chu was firmly convinced that his plan was sound. When the boat finally came to a steady stop at the shore, he sprang into the water, following the mark he’d carved into the hull—and began searching frantically for the lost sword. After scouring the depths for what felt like an eternity, he emerged from the water utterly defeated, his face etched with confusion: “The mark was right here—so why is my sword nowhere to be found?” It turned out that while the boat had been moving steadily across the river, the sword had come to rest motionless in the water. By tracing the mark along the moving hull in search of a stationary sword, he had only ended up chasing shadows—his efforts were destined to fail.