Obstruction tactics (also known as interference) are one of the most inspiring tactical patterns in chess.
Viktor Korchnoi is considered one of the strongest players never to have become World Chess Champion and in this game he demonstrates a beautiful obstruction tactic:

Diagram above: Black wants to play 1… h2 in order to promote the pawn, but white will simply play 2.Rb1 and stop the idea. How can black overcome the problem?
Scroll down to see the solution.
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Diagram above: 1… Rc1! Black realizes that white’s rook needs the first rank to stop the black pawn. Black finds a way to obstruct the first rank!
The point is that after either Kxc1 or Nxc1…

Diagram above: After 2.Kxc1 (or Nxc1) black plays h2 and now white’s rook will be obstructed if white wants to play Rb1. The black pawn will promote: 1… Rc1 2.Kxc1 h2 3.Rb1 h1(Q)+
Get More Obstruction Tactics
I made a collection of 20 hand-picked exercises that feature interference tactics (obstruction). You can get the complete set here:
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