In Judo, one of the most important things to understand is that it is primarily a **grappling martial art**. While there are various skills involved, we need to identify the skill that does not belong to Judo.
Out of the given options, **kicking** is the skill that is not a part of Judo. In fact, Judo specifically focuses on throwing and groundwork techniques rather than striking or kicking.
Let's briefly discuss the other skills mentioned in the options:
- **Gripping**: This skill is crucial in Judo as it involves controlling and manipulating your opponent's body by gripping their uniform (gi).
- **Stance**: A correct and balanced stance is essential in Judo. It provides stability, power, and control during throwing techniques.
- **Falling**: Falling or **ukemi** is an integral part of Judo. Proper falling techniques are taught to Judo practitioners to ensure their safety during training and competition.
Therefore, it is clear that **kicking** is not a skill in Judo, whereas gripping, stance, and falling are all fundamental aspects of this martial art.