Did some research in some MMA/grappling books I own and found out the true origin..
Kimuras and
Americanas are variations of similar arm locks.. They can both be applied standing but are mainly used in ground fighting.. In BJJ, if the wrist is moved towards the head, it is known as an
Americana, if the wrist is forced towards the hip, it is known as a
Kimura.. In Judo, both the hold are known as
ude garami ("arm entanglement"), while sometimes the Kimura is known as
gyaku ude garami or "reverse arm entanglement".. Catch Wrestler sometimes prefer the term
key lock,
figure four, or
double wrist lock.. Different disciplines, different nomenclature, but in mixed martial arts, it is the clear and useful BJJ terminology that dominates..
The term "
Americana" actually comes from legendary Wrestler Bob Anderson who trained with Rolls Gracie in the 1970's.. "I didn't go 'OK, I'm gonna show you the Americana Arm Bar and I'm the guy that invented it" Anderson recalls, "it just came out of what I knew, and what Rolls liked.. I didn't even know he called it the Americana because I'm the guy that went down there and showed them, and thats how the
American Arm Bar got started"..
The Kimura is named after Masahiko Kimura, a Japanese Judo legend, after he broke Hilio Gracies arm with the technique in their 1955 match caused the Graice corner to throw in the towel..
Reference:
The MMA Encyclopedia by Johnathon Snowden and Kendall Shields