The Vietnamese phrase "biết tay" can be translated to English as "to know what one is made of." It is often used in informal or colloquial contexts to express the idea of demonstrating one's skills, abilities, or strength, especially in a challenging situation.
In a more advanced context, "biết tay" can be used to challenge someone or to express confidence in your own skills. For example, during a competition or a debate, you might say, "Hãy xem ai sẽ biết tay ai!" which means "Let’s see who will show what they’re made of!"
While "biết tay" primarily refers to demonstrating one’s abilities, it can also imply a sense of rivalry or challenge between two people or groups.