What if you accidentally kill someone? I took the knife to defend myself and hit it directly on the opposite side. Can I ask a lawyer to prove myself right?

Whether the death of the other party was caused by careless self-defense with a knife and whether it can be judged as legitimate self-defense depends on the specific facts and legal provisions of the case. The following are some factors that may affect judgment:

Definition of justifiable defense: According to Article 20 of the Criminal Law of People's Republic of China (PRC), justifiable defense refers to the act of protecting the state, the public, oneself or others' personal, property and other rights from ongoing unlawful infringement, stopping unlawful infringement and causing damage to the wrongdoer. It belongs to self-defense and does not bear criminal responsibility.

Limits of justifiable defense: If justifiable defense obviously exceeds the necessary limits and causes great damage, criminal responsibility shall be borne, but punishment shall be mitigated or exempted.

Specific facts of the case: when judging whether it is justifiable defense, we need to consider the specific facts of the case, such as whether the other party is committing illegal infringement, whether the defensive behavior is necessary, whether it exceeds the necessary limit, etc.

The situation you described, if the other party directly hit you, may be regarded as an accident, rather than your initiative. However, the court will also consider other factors when making a judgment, such as whether you took defensive actions when the other party committed illegal infringement, and whether the other party's actions were enough to threaten your safety.

If you are worried that you may face criminal responsibility, I suggest you contact a lawyer as soon as possible.