A small, rectangular piece of paper used to determine a ninja's chakra nature. The paper is thin and lightweight, with a smooth surface that reacts vividly to chakra. When infused with chakra, it changes color or disintegrates based on the user's chakra nature, featuring vibrant hues like green for wind, blue for water, etc. The edges are slightly frayed, giving it a handmade appearance, and it may have subtle, faint symbols or markings indicative of its mystical properties.