I took a random guess at the answer and got it right.
guessing game
Frequency:
45
%
Their relationship turned into a constant guessing game.
educated guesswork
Frequency:
35
%
The success of the project was due to his educated guesswork.
Idiomatic Expressions for guessing
Phrase: Guessing game
Meaning: A situation where people try to predict or estimate something without all the information
Usage: The negotiations turned into a guessing game as both parties tried to figure out the other's intentions.