It’s not a quiz.
You need to know a lot, of course, but you’re not expected to have rapid recall or a photographic memory of your research and your thesis.
It’s not an interview.
You might choose to dress smart, but you’ve not applied for a position. The focus and purpose of the viva are radically different.
It’s not a game.
The people involved have roles but aren’t players. There are rules to be followed but there aren’t moves to make or best strategies to employ.
It’s not a question and answer session.
There are going to be lots of questions but the structure and flow is not simply question and answer, question and answer.
The viva is an exam.
The viva is a discussion.
The viva is a challenge, but one you can prepare for.
The viva is one more day to demonstrate your capability as a researcher.