Legal analysis: it depends on which content is more specific and which is better for litigation. If one of the IOUs and IOUs clearly states the loan amount, interest, use of money, repayment period, etc. It will be easier to go to court. However, going to court is not only about writing IOUs or IOUs, but also depends on other evidences that can prove the existence of the loan relationship and the debtor's failure to pay back the money, such as the recording of repayment demand and transfer records.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 675 The borrower shall repay the loan within the agreed time limit. If the term of the loan is not agreed or clearly agreed, and cannot be determined according to the provisions of Article 510 of this Law, the borrower may return it at any time; The lender may urge the borrower to return it within a reasonable period of time.

Article 678 The borrower may apply to the lender for extension before the repayment period expires. If the lender agrees, it can be extended.