This sealing technique works similar to a tracking device. A small invisible seal is placed upon a person, whether on the skin or the clothing. This seal actually holds a tiny bit of Gin's chakra within it, making it easier for him to locate who is he looking for. There are a few issues with this technique though. The first is the distance; if someone with this seal goes too far, the signal becomes harder to discern. The second issue with this seal is that the chakra within the seal does not last for very long, meaning it will expire in a week or two and the seal with dissipate.