Free tutorial & video on Crafting Happiness
https://craftinghappiness.com/half-granny-square

Half Granny Squares are a variation of the traditional granny square and they are useful in intricate designs for blankets, cardigans, and bags.

The most popular use for a half granny square is to fill the gaps and create straight edges when you join granny squares diagonally for blankets, or in garment constructions to shape the arm holes.