Janowski Variation
The Janowski Indian Defense, 3. Nc3 Bf5, was first introduced by Dawid Janowski in the 1920s, although it did not gain much popularity until the 1980s. Several top-level players have employed the opening multiple times, including Mikhail Tal, Bent Larsen, Florin Gheorghiu, and Kamran Shirazi.
The idea behind the variation is that by playing 3...Bf5, Black prevents White from immediately playing the space-grabbing 4.e4.
Read more about this topic: Old Indian Defense