1. Does the contract have to be stamped with a riding seal?

In daily signed contracts, the three signature methods, signature, thumbprint and seal, have the same legal effect and are protected by law. When signing a contract, both parties often prove that the contract is valid by signing and sealing, but the law does not point out that the contract is valid only by signing and sealing. If the contract is only signed or sealed by both parties, it is still valid.

Second, the validity standard of the contract

The criteria for determining the validity of the contract include the following aspects:

1, the parties have corresponding capacity for civil conduct.

Civil capacity includes contractual capacity and corresponding contracting capacity, which is the basic condition for the parties to understand and grasp the development and legal effect of the contract.

In principle, natural persons must have full capacity to sign contracts. If a person with limited capacity and a person without capacity cannot sign a contract in person, they should be signed by their legal representatives.

There is an exception in the Contract Law, where a person with limited capacity can independently sign a contract for pure benefit or a contract suitable for his age, intelligence and mental health.

For non-natural persons, they must have the ability to conclude contracts after legal procedures are established.

At the same time, we must have the corresponding contracting ability, that is, we must sign the contract within the scope of authority granted by laws, administrative regulations and relevant departments.

2. The intention of the parties is true.

The expression of a contracting party should truly reflect its inherent meaning of validity, that is, its meaning of validity is consistent with the expression.

If the expression of intention is untrue, the impact on the effectiveness of the contract shall be determined according to the specific circumstances.

In case of general misunderstanding, this contract is still valid.

If there is a major misunderstanding, this contract can be changed or terminated.

In the case that the contract is obviously unfair due to the danger of taking advantage of others, the contract can be modified or terminated.

A contract concluded by fraud or coercion is invalid if it harms the interests of the state; If it does not harm the interests of the state, the contract can be changed or terminated.

3, does not violate the law or social public interests.

4. The subject matter of the contract must be definite and possible.

The subject matter of a contract determines the quality and quantity of contractual rights and obligations. Without it, the contract will lose its purpose and positive significance and should be invalid.

The possibility of the subject matter of the contract means that the contract payment may be realized.

The determination of the subject matter of the contract means that the subject matter of the contract is determined or can be determined from the beginning.

Third, determine the standard of revocable contract.

The criteria for determining a revocable contract are as follows:

1, due to fraud, coercion or taking advantage of others' danger.

The contract concluded under the conditions of fraud and coercion obviously violates the voluntary principle of China's civil law: a contract signed by one party claiming that the other party is in danger and forcing the other party to make an untrue expression of will for illegitimate interests seriously damages the other party's interests is a contract concluded by taking advantage of the other party's danger.

2, due to a major misunderstanding, causing great losses to the misunderstood party.

If the actor has a wrong understanding of the nature of the act, the other party, the variety, quality, specification and quantity of the subject matter, which makes the consequences of the act contrary to his own expression of will and causes great losses, it can be considered as a major misunderstanding.

3. Because it is obviously unfair

According to China's judicial interpretation, obviously unfair refers to a civil act in which one party takes advantage or the other party is inexperienced, resulting in the rights and obligations of both parties obviously violating the principles of fairness and equal compensation.