As two jar said, learn basic grappling, best advice. Two systems I am familar with that focus on weapon retention and disarming techinques are Krav Maga and Toney Blauer’s Spear system.
Some additional information:
Hand-to-Hand Combat in Confined Spaces]
Urban environments; narrow alleys, crowded public transport, tight stairwells etc. Techniques for these specific scenarios, focusing on maximizing limited space and using the environment to one’s advantage.
• Spatial Awareness: The first step in confined space combat is to be acutely aware of your surroundings. This includes understanding the limitations and potential uses of the space, such as…
• Escape Routes: Always identify potential escape routes. In a high-stress situation, knowing your exit options can be as crucial as the combat itself…
• Use of Environmental Objects: In confined spaces, using the environment to your advantage is key. This can mean leveraging walls…
• Close-Range Strikes: In confined spaces, there’s limited room for wide swings or long-range kicks. Focus on…
• Control Techniques: Grappling and control techniques are effective in confined spaces. Techniques like joint locks…
• Defensive Postures: Adopt a narrow stance. This minimizes your profile and makes it more…
• Low-Line Attacks: Targeting an opponent’s lower body (knees, shins) can be particularly effective in tight spaces…
• Breaching Techniques: When moving through doorways or narrow passages, use breaching techniques that allow you to quickly…