課税対象額, or "taxable amount," refers to the portion of an individual's or entity's income or assets that is subject to taxation under Japanese law. This amount is determined after various deductions and exemptions are applied to the gross income or total asset value. It forms the basis for calculating the amount of tax owed to the government. Understanding one's taxable amount is crucial for accurate tax reporting and compliance, as it directly affects the tax liability. Proper calculation ensures that taxpayers neither underpay nor overpay their taxes, thereby avoiding potential penalties and ensuring that they fulfill their legal obligations.

ワンストップ特例申請書, or "One-Stop Special Application Form," is a document used in Japan for the simplified handling of certain tax procedures related to the furusato nozei program, allowing taxpayers to manage the allocation of their hometown tax payments (ふるさと納税) through a single application process, instead of dealing with multiple local government offices individually. This form streamlines the administrative process, making it more convenient for taxpayers to allocate their contributions to different localities, and ensures that the tax benefits are properly distributed. This system is particularly useful for those who make donations to multiple municipalities, as it consolidates the reporting and management into a single step, saving time and reducing paperwork.

マイナンバー (My Number) refers to Japan's social security and tax number system, which assigns a unique 12-digit identification number to each resident of Japan, including both Japanese citizens and foreign residents. The My Number system aims to streamline and improve the efficiency of administrative processes related to social security, taxation, and disaster response.

The My Number is used for various purposes, such as filing tax returns, applying for social security benefits, and accessing public services. It helps in reducing administrative burdens, preventing fraud, and ensuring accurate identification of individuals in government records.

Residents receive a My Number notification card, followed by an optional photo ID card that can be used for identification purposes. The use of My Number is strictly regulated to protect personal information and ensure privacy.