Ken vs Ryu
Ken and Ryu are characters in the popular fighting game Street Fighters. In the Capcom universe, Ken and Ryu are originally sparring partners and best friends. Both have goals to test their powers against many different fighters and strive to become stronger.
Originally, both characters featured the same moves and powers. The only distinguishing factor was how they looked. Over time, however, Capcom differentiated the two fighters in their fighting styles as well.
Ken is an American with long blond hair while Ryu is a Japanese with short black hair. Ken wears red while Ryu wears white. Ken is usually depicted barefoot, while Ryu originally had red shoes.
 Fighting styles
Both Ryu and Ken are practitioners of a fictitious martial art rooted as an assassination style. Both Ryu and Ken learned their art from Gouken, who refined the style as a purely combative non-killing style. Capcom USA originally referred to Ryu's fighting style as "Shotokan" despite bearing little resemblance to the discipline. As the Ryu character is based on the real life events of both Yoshiji Soeno and his sensei Ōyama Masutatsu, who were practitioners of kyokushinkai karate, the traditional kyokushinkai techniques can be clearly seen in the character's fighting style.
While Ryu and Ken follow the same martial arts discipline, as the Street Fighter series evolved, the differences between the two characters was portrayed by their attacks: Ryu focused on technique while Ken opted for stylish unpredictability.
His Shōryū-ken (昇龍拳, "Rising Dragon Fist") does only one hit, so Ryu can effectively use this move at full power against airborne opponents. Ryu focuses more on the Hadou principle of his style, which translates to him being very skilled with his usage of ki - Ryu has the most concentrated Hadōken (波動拳, "Surge Fist") amongst all users. In addition, Ryu has mastered the Tatsumaki-Senpū kyaku (竜巻旋風脚, "Tornado Whirlwind Kick"), a powerful kick performed in mid-air. Ryu has been given special moves in various games, among those, Jōdan Sokutō Geri (上段足刀蹴り, "High Side Kick"), a fast side kick only available to him in the iterations of Street Fighter III.
Ken mainly focuses on the Shōryūken move, to the point where his Shōryūken sets the opponent aflame. Ken's Tatsumaki Senpūkyaku does not allow him to dodge projectiles at the start of the spin as Ryu's does, but spins faster, allowing him to hit his opponent up to five times (without knocking down). Ken's Hadōken is less concentrated (and therefore slightly slower) than Ryu's, but Ken's Shōryūken has more range and does more damage than Ryu's as it can land up to three hits if performed in close proximity. All in all, Ken, Ryu and Akuma share virtually all the same strategies and special moves, with a few minor differences between them.