For some time in Japan, Judo and Jiu-Jitsu were almost synonymous. Judo was known as Kano's Jiu-Jitsu. Regardless, this answers the question, "why do they call it Brazilian Jiu-Jitsu and not Brazilian Judo?" Because they were essentially the same thing at the time, remember, the Gracie family was learning Jiu-Jitsu and Judo while Kano was still struggling to show the difference between the two and popularize his art. In the early 1900's there was very little difference between the two. In fact, Judo was merely a collection of Jiu-jitsu styles, whose strongest points were put together to make what then became Judo. The Gracie family was introduced to Judo at a time when the Kodokan had recently suffered a great defeat to the grappling style of the Fusen Ryu. This can be compared to the Ultimate Fighting Championship of the early 1990's, when most martial artists were attempting to fight Royce Gracie standing. They would all eventually find themselves on the ground, where they were at a loss as to what to do. Consequently, grappling became very popular over the next ten years and many styles began to incorporate grappling techniques into their curriculum. Royce Gracie was simply doing what had already been done in the early 1900's by the Fusen Ryu to Judo practitioners of the Kodokan, so we can easily draw the conclusion from the experience in our own time that when Meada arrived in Brazil, he was a student of a Kodokan that was adding "new" grappling techniques to its system.
To show gratitude to Gracie for his help in the colonization, Maeda taught Gastao's son Carlos the basic techniques of Jiu-Jitsu. Carlos Gracie then taught his brothers Oswaldo, Jorge, Gastao, and Helio. In 1925 the brothers opened their first school, and Jiu-Jitsu was cultivated into a more effective martial art and sport known as Brazilian Jiu-Jitsu. What made this version of Jiu-Jitsu more effective was the constant exposure of its practitioners to real situations. Between their own schools, Brazilian Jiu-Jitsu players would compete in a sportive way to keep the techniques of their art sharp. The Gracie family would issue a challenge to all others to fight without rules. In these no rules or '
vale tudo' fights, the Gracie family and their students would evaluate the techniques of their fighting art.
a to caly artykul :
http://www.jiu-jitsu.net/history.shtml
po angielsku ale dobrze sie czyta wkleilem fragment ktory traktuje o bjj nazywanym na poczatku XX wieku vale tudo i teraz w sumie tez.
Milej lektury bardzo dobry artykul polecam kazdemu