In case of emergency, the use of surrounding items to make simple self-defense devices must follow the principles of legality, safety, and quick entry into force. The following are the creative use plans and key skills of 10 common items： ###1. Ready-to-use tools 1. **Metal key** -Usage: Clip the longest key between the fingers, with the tip facing out, forming a "finger tiger” effect -Target: Quickly poke the attacker's eye socket, throat, or palm of the tiger's mouth -Note: Hold the key tightly to avoid slipping off, and cooperate with horizontal movement to create an opportunity to escape. 2. **Fountain pen/ballpoint pen** -Modification: Remove the pen cap and wrap the pen holder with tape to increase friction -Tactics: Reverse grip the pen holder (the tip protrudes from the side of the thumb) and attack the neck or clavicle with an uppercut trajectory -Data: Ordinary ballpoint pens can produce a puncture pressure of about 30psi ###2. Transformation of personal belongings 3. **Folding umbrella** -Advanced usage： ① After spreading the umbrella surface to block the opponent's line of sight, poke the knee with the tip of the umbrella ② When the umbrella is closed, hold the head of the umbrella in your hand and stab the ribs with a metal tip. -Advantage: Create a safe distance of 1.5 meters, and the metal umbrella bone can withstand the impact of 50kg 4. **Belt defense technique** -Quickly untie it: keep the metal buckle in your right hand and straighten the belt with your left hand -Attack method： -Wave the metal buckle to hit the temple (circular attack) -Wrap around the opponent's armed wrist and pull to destroy the balance ###3. Strengthening of daily necessities 5. **300ml plastic bottle** -Efficiency-enhancing modification: load 200ml of sand and gravel and fill with water to full -Use: Hold the mouth of the bottle in your hand as a meteor hammer, which generates about 5J of impact energy when swinging -Science: The momentum transfer efficiency of liquid + solid mixture is 40% higher than that of pure liquid% 6. **Smart phone** -Defense mode： ① Turn on the flashlight flashing function (>120 lumens can cause temporary blindness) ②The corners of the nose are used to attack the bridge of the nose when holding the mobile phone (the hardness of the body is莫Mohs 4.5) -Note: Give priority to the use of the alarm function to avoid damaging the communication tool ###4. Special situation plan 7. **Book reinforcement** -Best choice: 32-open hardcover hardcover book (about 1.5 kg) -Usage： -Hold the book vertically to block the knife attack (the paper fiber can disperse 30% of the cutting force) - Move 90 degrees sideways immediately after throwing the book 8. **Coin tactics** -Throwing skills: Grab 3-5 coins and throw them at the opponent's face at an angle of 45° -Data: Throwing accuracy within 5 meters reaches 70%, which can create a 2-second escape window ###5. Biochemical Defense Plan 9. **Chili spray substitute** -Efficient formula: mix 1:1 pepper powder + talcum powder into a vial with nozzle -Effect: It can cause a burning sensation of breathing for 15-30 seconds, and the jet distance is up to 1.2 meters. -Warning: If used against the wind, it will bite back. Close the air and evacuate immediately after spraying. ###6. Core principles -**3-second rule**: Any defensive action must be completed within 3 seconds and then evacuated -**Human weakness priority**: Eyes> Adam's apple>knees>tibia>groin -**Legal red line**: Avoid using sharp objects to cause permanent damage, and the degree of defense must be equal to the threat. It is recommended to conduct regular **5-minute scenario simulation training**: Use the above items to practice quick access, mobile attack, and escape route planning. Remember, 80% of successful self-defense depends on observing the environment in advance and making rapid decisions. Tools are only aids.