In his first case he is defending his client against an accusation of robbery. He doesn't bring up evidence that immediately proves his client not guilty like other lawyer novels.

Firstly, he is able to argue that the client was under duress in the actual crime scene due to the armed criminals telling him to take the money.

Secondly, there was a previous case with the bank where a couple got robbed in the bank. The bank said that it was not liable because once the money left the counter the bank wasn't responsible. Using this same logic, he said that his client shouldn't be liable. The judge didn't actually agree with this specific reasoning, but instead the bank was deemed sort of guilty in their previous case. This kinda of shows that the MC doesn't win every argument

This Specific argument takes place in chapter 12