Indian positions are very complicated, I will tell some of the opening theory.
1. 2nd move
2. Openings
3. Games
Second move
In the Indian game, for the second move white usually plays c4, creating a strong center. Second most popular is Nf3, then rarely, white may play the Trompowsky attack.
C4 is by far the most popular move. It has been played 430,000+ plus times out of about 625,000 positions. Then Nf3 has been played about 160,000 times out of 625,000 times, then Bg5 has been played about 25,000+ times.
Down below are the second move lines
Openings
Now I will be telling some of the Indian OPENINGS.
1. Kings Indian Defense
I think this is one of the most common Indian openings.
This is the starting position of the Kings Indian defense
In the kings Indian defense, black allows white to build a strong center, while trying to undermine the center and fianchettoing the bishop. Also, in the kings Indian defense there is one very common line, the other lines are very rare.
Down below is the most common line
Queens Indian Defense
This is the starting position of the Queens Indian Defense
In the Queens Indian defense, black prepares to either fianchetto his bishop OR put pressure on c4 by Ba6. The Queens Indian Defense is usually followed up by g3, preparing to fianchetto whites light squared bishop, 2nd most popular variation is the Petrosian variation, which is 4. a6, preventing the bishop or knight to go there. Then the 3rd most popular variation, the Kasparov variation, which is 4. Nc3. The Kasparov can transfer into the Nimzo Indian defense.
Down below are common lines
Nimzo Indian defense
Down below is the starting position of the Nimzo Indian.
The Nimzo Indian has lots of lines, there are 2 very common ones, but there are 9 variations that have been played at least 700 times, the most common lines is the normal line (4. e3) and the classical variation (4. Qc2). The third most common move is Nc3, which is the three knights variation. In the Nimzo Indian black tries to force doubled pawns on the c file and possibly make an attack on e4 or c3 later on. Another popular option is 4. f3, preparing the e4 push so if black takes the knight white can still make an e4 push. The most popular options in order most popular to least popular is e3, Qc2, Nf3, f3, a3, Bg5, Bd2, Qb3.
Down below are the most popular lines
Bogo Indian Defense
This is the starting position of the Bogo
The Bogo Indian aims to trade dark squared bishops and can possibly transfer into the Nimzo Indian by Nc3, since this opening is MUCH less common then other Indian openings I won't explain it much 
Games
Now I will be sharing some games featuring these openings
Hikaru vs Magnus 2016
Karpov vs Kasparov 1991
Euwe vs Alekhine 1937
Carlsen vs So 2017
Spassky vs Fischer 1992
Hopefully you enjoyed this blog!!!!!
