Theory:-The Nimzo-Indian Defense is a chess opening characterized by the first three moves:
Here in this article we will primarily focus on f3 as fourth move played by White which is called Kmoch variation
f3 variation/Kmoch variation:
Here Black has two choices mainly (1)c5 variation & (2)d5
Who should play Nimzo-Indian (f3 variation/Kmoch variation)?
Though, there is no hard and fast rule as to who should try this variation, however it is suggested that one possesing deep understanding of positional play should be trying the f3 variation. The variation has never been out of trend as there had been a match between Firouza and Ding Leren in FIDE World cup 2019.