I really don’t think anybody can answer this question however there are loads of hypotheses. Every culture has some kind of hand. Combat without weapons appear at times and in the shape of wrestling boxing. A really hypothesis that is good is the wrestling methods of Jiu-Jitsu could have come from Greece. Games were among the most powerful traditions of the Greek. It is probably that combined with Greek thoughts, came among its most well-known sports, Pankration. Pankration was a game that included both wrestling and boxing methods and became increasingly more popular to the Greeks than either of these sports independently. The Roman Gladiators would afterwards overshadow pankration, then banned by leaders of the Roman Empire by the Olympics. Though new rulers would go and come, Greek traditions and thoughts still reached India, where Jiu-Jitsu’s base was supposed to have already been born. Throughout Alexander the Great’s conquests (356 – 323 B.C.), he attracted the Greek civilization into the areas he defeated.
The Chinese have a Deal of tales to encourage the arts’ background. The overall notion adopted by the majority of historians is the fact that jelqing martial arts practices came from India together with Buddhism (Bodhi Dharma). The idea here is the Shaolin temple was constructed at the middle of China and that is where Bodhi Dharma introduced Buddhism and Boxing (senzuikyo). (ref. Aikido and Chinese Martial Arts, Sugawara and Xing) The narrative that affirms the Notion of Jiu-Jitsu coming from China occurs around the time of the collapse of the Ming Dynasty. It says that a guy named Chingempin came from Japan to reside in Tokyo in a Buddhist temple in which he met three Ronin (masterless Samurai) called Fukuno, Isogai and Miura. Chingempin told an art he’d seen in China’s Ronin. The Ronin became especially interested in pursuing the study of the artwork, so he began teaching in Japan and also this artwork became Jiu-Jitsu.
The theory is There was of wrestling which had grown in China, kinds. Among the most noteworthy is Horn Wrestling. This kind of wrestling evolved to Jiaoli, which was wrestling with no horns and has been practiced by the Mongolians. This kind of wrestling could be understood in Native American civilizations (obvious in the standard Native American Buffalo head wear) and probably arrived there by means of Mongolians migrating through modern Alaska. Jiaoli turned into Xiangpu and evolved also it is said that this kind of wrestling became Sumo in Japan. Another theory claims that there were professionals of Chikura Karube, a wrestling game produced about 200 B.C. It is stated that Chikura Karube became Jiu-Jitsu in Japan. Find more info here https://bjjgireviews.com/best-bjj-gi/.