The fundamental principles of sambo include a combination of throws, ground fighting, and submission techniques. Sambo places a strong emphasis on balance, leverage, and using an opponent's energy against them. Techniques involve both standing and ground combat.

Sambo is called the "invisible weapon" because it equips practitioners with a versatile set of skills that can be used in various combat situations. Its adaptability and effectiveness make it a powerful tool, much like a hidden or "invisible" weapon.

Some advantages of training in sambo compared to other martial arts include its versatility, as it combines elements of both standing and ground combat. Sambo is also known for its practicality and effectiveness in real-life self-defense situations. Additionally, it fosters physical fitness and discipline.

Sambo is indeed suitable for self-defense in real-life situations. Its focus on practical techniques, including throws, joint locks, and ground control, provides effective means of defending oneself in close-quarters combat. However, like any martial art, proficiency and adaptability depend on the individual's training and experience.