Four Symbols: Time's Forgiveness

This is the secret behind Nishi's youth despite her considerably advance age. Taking the famous Four Symbols Seal, she applies it to her stomach after utilizing the standard way to change one's appearance. The seal acts as a catalyst toward preventing the aging of the user's body, allowing them to retain the appearance of their younger selves by sealing off the progression of their body's clock. The seal remains active even if the user is knocked unconscious, though like the normal Four Symbols, it can weaken over time. However, by placing the seal directly on the stomach of the user and centered over one's chakra signature, it is possible to link them, potentially allowing the user to retain their youthful physique indefinitely. It is rumored that Tsunade uses an incomplete version of this technique.