The basic internal assessment method is a method used to evaluate the credit risk of banks. Credit risk management techniques refer to various tools and methods used to reduce or disperse risks in credit risk management. In the first-level internal evaluation method, credit risk mitigation tools mainly include the following:

1. Collateral: Collateral means that the debtor takes specific assets as collateral to protect the rights and interests of creditors in case of debt default. If the debtor defaults, the creditor can reduce the loss by disposing of the mortgaged assets.

2. Net settlement: Net settlement refers to the consolidation of multiple transactions into a net, which is used to calculate the risk exposure. This technology can reduce risk exposure, thus reducing credit risk.

3. Credit derivatives: Credit derivatives are financial contracts used to manage credit risks. For example, credit default swaps (CDS) can compensate one party (seller) when the debtor defaults, thus reducing the credit risk.

4. Insurance: Insurance is a common risk mitigation tool and can be used to manage credit risk. For example, when the debtor defaults, credit insurance can provide compensation for creditors.

5. Hierarchical structure: Priority structure refers to the debt structure that distinguishes debts with higher priority (such as priority debts) from debts with lower priority (such as subordinated debts). This structure can reduce the risk exposure of priority creditors, thus reducing credit risk.

It should be noted that the selection and use of credit risk mitigation tools need to be comprehensively considered according to the bank's risk management strategy, regulatory requirements and business needs. At the same time, credit risk mitigation tools may have limitations, such as the liquidity of collateral and the complexity of credit derivatives, which need to be fully evaluated and weighed by banks in specific applications.