The Strength of a Hundred Seal - which takes the form of a diamond on the user's forehead - is used to gradually build up and store the user's chakra over time. Yin Seal: Release opens that seal, giving the user access to the accumulated chakra. Upon release, a pattern starts to appear from the diamond shape, spreading out across their forehead and potentially the rest of their body; by spreading the seal's pattern to another, the user can transfer the seal's chakra to them instead. The stored chakra amounts to far more than what the user has on their own, allowing them to perform chakra-demanding jutsu that they wouldn't be able to use otherwise, such as Creation Rebirth. If not all of the chakra ends up being used, it can be stored in a new Strength of a Hundred Seal.