What are the differences between these? I have so many opportunities to use them, but i haven't been taught them yet in class. I'd like to know what the differences are so i make sence more when describing them in training.

I thought they were all the same

i thought that too, but then i asked myself...why 4 names for the same technique?

A kimura is a figure 4 going the opposite direction (Sakuraba on Royler). A key lock, Americana, and figure 4 are the same thing.

Kimura:
http://www.bjj.org/techniques/aranha/kimura/

Americana, sometimes called figure 4, armlock, shoulder lock, or Keyock
http://www.bjj.org/techniques/aranha/valetudo/

awesome, thanks for the info and links Beelzebub :)

yeah, bub's right. they are all the same thing but different ways of performing it. i normally have been taught that the figure 4 was just the easiest way to describe the actual move. i never really called the figure 4 a move, but more like a description of a move.

I always call it a keylock when I'm on the ground but wqhen I'm standing I always call it a kimura for some reason.

an americana/keylock is then the elbow is pointing down and you have to bring the elbow near the rib for the lock to work. the kimura is when you have to bring the elbow far from the body

A kimura is a figure 4 going the opposite direction (Sakuraba on Royler). A key lock, Americana, and figure 4 are the same thing.
I always considered em all the same. So kimura goes the opposite direction. Learn something new every day.

The "Keylock" verison is much more painful too LOL

I call it "I ****ed up somewhere"

I call it "I ****ed up somewhere"
YEAH!! I knew someone knew what I was sayin ... sometimes it works, sometimes ....

interesting information (from the link on the George Mehdi thread) on the "Kimura" origin. Here is an exerpt:

"Mehdi gave up on Gracie jiu-jitsu and went to Japan immediately after the American Occupation ended in 1952. Among others, he trained with Kimura Masahiko, who defeated Helio the year before. He stayed five years as a student at Tenri University in Nara. Kimuras’s fight with Helio, Mehdi says, "was a joke". Kimura agreed to stall for 10 minutes, Mehdi says, to give the fans their money's worth and begin fighting after that. Mehdi imitated Helio's footwork in the match, exaggerating its awkwardness. Thirteen minutes into the fight, Kimura finished Helio with a shoulder lock, which the Brazilians now call "Kimura" in his honor ("don't call it "Kimura", Mehdi admonishes—it's ude garami"). There was some talk of fixing the actual outcome of the fight, but the Japanese embassy reportedly warned Kimura that if he lost he wouldn't be welcome back home in Japan anymore. A certain degree of choreography could be accepted but for Japan’s greatest champion to lose to a scrawny gaijin, that would be too much. "