Regulations Governing the Use of Uniform Invoices Article 22
For unused blank uniform invoices purchased for the term, business entities shall cut away a corner to nullify them and retain them for sampling inspection by tax authorities and shall indicate the alphabetic code and the starting and ending uniform invoice numbers of such invoices on the uniform invoice breakdown statement.
中文原文 統一發票使用辦法第22條
營業人對當期購買之統一發票賸餘空白未使用部分，應予截角作廢保存，以供稽徵機關抽查，並於填報統一發票明細表載明其字軌及起訖號碼。