Stand directly over the indent for 3 seconds. The shadow clock will appear below you, showing a random time between 1:00 and 11:00. You need to rotate the clock to 12:00.
Here's the step-by-step guide for Walkthrough 126: Hizashi No Naka No Real Walkthrough 126
Guide to Hizashi no Naka no Real: Complete Interaction Walkthrough Hizashi no Naka no Real (also known as Real in the Sunlight Stand directly over the indent for 3 seconds