Russian roulette (ロシアン・ルーレット Roshian rūretto) is a game of chance, where players risk lethally shooting themselves. It is done by placing one or more rounds within a revolver gun, spinning the barrel, pointing the gun to one's head, and pulling the trigger, not knowing if a loaded chamber will be fired.
After being humiliated by Maximillion J. Pegasus, Bandit Keith tried to drown his loss with alcohol and drugs. With nothing left to lose, he joined an underground gambling circuit and played Russian roulette. Keith referenced this event when he Dueled Katsuya Jonouchi. He asked if Jonouchi had ever risked his life, while pointing his finger to his own head, mimicking a game of Russian roulette.
As punishment for Keith cheating in the Duel with Jonouchi, Pegasus inflicted the "Hand and Gun" Penalty Game on him. This transformed Keith's hand into a gun, which he was forced to use to play Russian roulette, killing himself.
Ryuichi Fuwa, while demonstrating his luck, guessed the combination to Seto Kaiba's safe, took the gun out of it and loaded all but one of the gun's chambers, before playing and surviving a game of Russian roulette.
Mokuba Kaiba played a game, which he called "Russian Roulette Dinner". Meals, some of which were poisoned, were placed on a rotating table. Players would spin the table and eat whichever meal stopped in front of them. However Mokuba cheated by having prior knowledge of which meals were poisoned and the ability to stop the table at a meal of his choosing.
Bandit Keith's card "Barrel Dragon" had an effect called "Russian Roulette". "Barrel Dragon" had three revolvers each with three of six chambers loaded. It attacked by spinning the barrel on each revolver and shooting a bullet if they stopped on loaded chambers, allowing it to attack up to three opposing monsters at once.
- Russian roulette on Wikipedia