Both sides of Atlantic flipping over party puzzle (6)

I believe the answer is:

sudoku

I'm a little stuck... Click here to teach me more about this clue!

'puzzle' is the definition.
(I know that sudoku is a type of puzzle)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for sudoku that I've seen before include "Boxing contest" , "Puzzle involving the numbers 1 to 9" , "Numbers game" , "Popular number puzzle" , "Number game" .)

I've seen this clue in The Everyman puzzle in The Observer.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.