Source : phlearn.com

The rule of thirds is the most basic type of composition and must be understood by a photographer. This technique divides 9 squares of equal size and places points of interest on lines or points on fields that are divided into 3.

POI has 4 points, while interesting lines are divided into 2 horizontal lines and 2 vertical lines. POI itself is stored on the four lines or points which are the eye parts of the object or object itself.