This Japanese legal guide simplifies the complex topic of "limited capacity persons" and "third-party protection" for the judicial scrivener exam. It categorizes individuals like minors, adult wards, persons under curatorship, and persons under assistance based on their legal ability to enter into contracts, distinguishing between actions that are "void" (invalid from the start) and those that are "cancelable" (can be undone). A critical focus is placed on how these distinctions impact the protection of "good faith third parties" who may have acquired rights through a contract with a limited capacity person, with the general rule being that void contracts offer no protection to third parties, while cancelable contracts do if the third party acted in good faith. The guide also highlights common exceptions, such as everyday purchases or actions that solely grant rights, and uses memorable phrases and examples to aid understanding.