 A fighting game is a video game genre based around interpersonal combat between a limited amount of characters in which they fight until they defeat their opponents where the timer expires. The fight matches typically consist of several rounds and take place in an arena, while each character has differing abilities but each is relatively viable to choose. Players must master techniques such as blocking, counter attacking, and chaining attacks together into combos. Starting in the early 1990s, most fighting games allowed the player to execute special attacks by performing specific input combinations. The fighting game genre is related to but distinct from beat them UPS, which involve large numbers of enemies against the human player. The first game to feature fist fighting was Heavyweight Champ in 1976, but it was Karate Champ which popularized one-on-one martial arts games in arcades in 1984. The following year, Yair Kung Fu featured antagonists with differing fighting styles, while the wave of the exploding fist further popularized the genre on home systems. In 1987, Street Fighter introduced hidden special attacks. In 1991, Capcom's highly successful Street Fighter II refined and popularized many of the conventions of the genre. The fighting game subsequently became the preeminent genre for competitive video gaming in the early 2000s, particularly in arcades. This period spawned dozens of other popular fighting games, including successful and long-running franchises like Street Fighter, Mortal Kombat, Super Smash Bros., Tekken, Guilty Gear, The King of Fighters, Virtua Fighter, Marvel Vs. Capcom, Killer Instinct, Blast Blue, Skull Girls, Dark Stalkers, Dead War Alive and Soul Calibur.