The Jogless Join is used when working crochet rounds only when you are not changing colour. The difference being you are not snipping the yarn each round and joining anywhere you please.
A jogless join is used at the end of a round. This method allows you to start a new round without leaving any visible joins behind as they tend to leave a line of demarcation. It should look seamless.
When you reach the end of a round follow these instructions: