Chain Puzzle

Chain Puzzle:

This question will be asked in the technical round in some Interviews just to check how to think?

Question:

A chain is broken into 3 pieces of equal length containing 3 links each. It is taken to a blacksmith to join into a single continuous one. How many links are to be opened to make it?

Answer:

2 links have to be opened. Open the second link on both sides. Therefore, 2 links are opened.