The Pirc(pronounced peerts though can be wrongly said as perk even among GMs)Defense which is played by the moves e4,d6,d4,Nf6.
The defense is named after the Slovenian International Grandmaster Vasja Pirc.Its most common sequence after Nf6 is Nc3 and g6. This is a relatively new opening because it orignally was a sideline and "irregular". It gained popularity after WWII(World War 2).
There are famous games from the Pirc Defense such as Fischer vs Spassky(it ended in a draw) and Fischer vs Korchnoi(Viktor Korchnoi won).The Fischer vs Korchnoi game had some blunders especially at the end when fischer resigns though the knight attacks the black queen!
The next game may get you thinking,"Why couldn`t Spassky win?". He has 2 rooks and Fischer has 1 but Spassky is only up a pawn in the end.Fischer draws in Game 17 against Boris Spassky for the World Title in Reykjavik, Iceland.
Here is the link to learn more:
Note: The picture at the top of the blog post shows Bobby Fischer.The game Spassky vs Fischer was played in 1972.