Doggy Racing is a mini-game in The Legend of Zelda: Majora's Mask. It is run by Mamamu Yan at the Doggy Racetrack in Romani Ranch. Throughout the mini-game, Link bets on dogs that compete in a race around a track. If Link bets on a dog that comes first, he will win triple the amount he bet. If the dog he bets on comes second, he will win double the amount he bet. If Link bets on a dog that comes third through fifth, he will break even and receive his bet back. If the dog Link bets on comes in sixth or worse, he will lose his bet. Link can bet only in multiples of 10, and the maximum he can bet is 90 Rupees, making the maximum amount he can win 270 Rupees. If Link wins over 150 Rupees, he will receive a Piece of Heart from Mamamu Yan. This only happens the first time he wins over 150 Rupees.
Link has no way of telling which dog will win unless he has the Mask of Truth, obtained from the Southern Swamp Spider House. Using the Mask of Truth, if Link picks up a dog, he can read its thoughts, which show how well it will do in the race. Any dog that says something along the lines of "I'm unstoppable, there's no way I can lose!" has the highest chance of winning, or it will at least finish in the top five, so that Link will not lose any Rupees.