Thumb wrestling is a contest where two players, while facing each other, hold their left or right hand in a thumbs up gesture. They lock hands with each player curling their fingers with the other player's fingers. The thumbs are still extended pointing upwards. The objective is to pin the opponent’s thumb, which is often to a count of three. A player may not use any other fingers in their hand other than the thumb. Players can deploy various tactics to wear the opponent out. An example is to knuckle first to wear your opponent out before going for the pin. Another tactic is to sneak or feign attacks to catch your opponent by surprise. A specially designed ring, like a miniature boxing ring with two holes in the floor for the thumbs, is used for competitions. Players can duck their thumbs in the hole as a tactic to avoid defeat, known as a Rabbit Hole maneuver.  

The origin of thumb wrestling is not that clear, but various claims have been made that the contest initiated as far back as the 1930s and 1940s. The sport is taken very seriously, especially in the United States where it has been referred to as a game of ‘the miniature golf of martials sports’ by the San Francisco Chronicle. Thumb wrestling does not have an international governing body, but there is a World Championship. The most recent event was hosted in the United Kingdom. It is gaining popularity worldwide, especially with nations in East Asia.