IN THIS LESSON YOU WILL LEARN WHAT PINS ARE AND HOW TO USE THEM

To the right white has pinned a pawn to blacks king.

Black did not notice the pinned pawn or the basically hanging knight and moved a pawn to h6 instead and in return black knight gets taken and the pawn cannot re-capture and if the queen recaptures whites queen will re-capture.

This is the power of pins.

A pin is where a piece cannot move because then the piece behind it will be vulnerable to be captured, in this case its an absolute pin because the king cannot be revealed to a check.