Two countries flipped over the same newspaper feature (6)
I believe the answer is:
sudoku
'same newspaper feature' is the definition.
The definition suggests a singular noun which matches the answer.
'two countries flipped over' is the wordplay.
'two countries' means two replacements for 'countries'.
'countries' becomes 'udo' (I am not sure about this - if you are sure you should believe this answer much more).
'countries' becomes 'UKs' (UK is an example).
'flipped' says the letters should be written backwards.
'over' indicates putting letters inside.
'uks' reversed gives 'sku'.
'udo' inserted within 'sku' is 'SUDOKU'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for sudoku that I've seen before include "Numbers game" , "Numerical puzzle" , "Number placement puzzle with a 9 x 9 grid" , "(Usually) nine-by-nine numbers puzzle" , "9 x 9, 1-9 puzzle" .)