Two IOUs were written on a piece of paper, and the debtor only signed one. Although it was effective, the risk was huge.

Writing only two words of IOU on a piece of paper and signing it means that I acknowledge the IOU, but there are great hidden dangers and it can easily be exploited by others. If money or property is filled in, you should be responsible for repaying it. Therefore, the amount owed should be written down, and the number should be written in capital letters to prevent it from being tampered with.

An IOU is a document written by an individual or unit to the relevant unit or individual when they owe money or property. IOUs are also called "white notes" today. IOUs are also common written documents in daily life that are written to prove that one party owes another party property. It is a type of voucher application style.

The content of the IOU should be sufficient and clearly stated. It generally consists of three parts: title, body and payment.

(1) Title. The title of an IOU generally consists of the name of the genre, that is, the word "IOU" is written in a larger font in the middle above the text. Some also write the words "arrears" or "owe now" as the title in this position, but the text of this title is written in the top box of the next line.

(2) Text. The text of the IOU should state clearly who or what unit is owed, what the amount is, and the date of repayment should be indicated.

(3) Signing. The payment must be signed with the name of the debtor's unit and the signature of the person handling it. If the IOU is issued by an individual, the name of the individual who owes the debt must be signed. And also sign the date of the IOU. The unit's official seal must be stamped, and the individual's private seal must be stamped.