"Ken Masters (ケン・マスターズ) is a video game character created by Capcom. As a main character, he has appeared in all of the Street Fighter games along with his best friend and rival, Ryu. Like Ryu, Ken's goal is to test his power against many different fighters and strive to become stronger.
Since the original Street Fighter, Ken has been consistently depicted with neck-length blond hair, black eyebrows and wears a red sleeveless keikogi with a black belt. In the original Street Fighter, Ken fought barefooted (unlike his rival Ryu, who originally wore red slippers and began fighting barefooted in subsequent games) and wore yellow arm bands instead of gloves.
In Street Fighter II his appearance remained mostly unchanged from the original, with his yellow arm bands replaced by brown gloves. In concept art for the original Street Fighter II, the sleeves on Ken's gi are depicted to had been cut seamlessly from his tunic (in contrast to Ryu's sleeves, which feature a more torn appearance).
The Street Fighter Alpha prequel series features a younger Ken than depicted in Street Fighter II and other games. He wears yellow gloves, similar to the yellow arm bands he wore in the first game, but has much longer hair, which he holds together with a red ribbon as a ponytail, much like his appearance in flashbacks in Street Fighter II: The Animated Movie. Like in the animated movie, Ken gives his red ribbon as a gift to Ryu in his ending in Street Fighter Alpha 2, which becomes the red headband Ryu wears in Street Fighter II on forward."
Source: Wikipedia, "Ken_Masters", available under the CC-BY-SA License.