Red Coin
Red Coins were first seen in Super Mario World 2: Yoshi's Island, in which they were hidden behind regular Gold Coins. The only way to tell which Gold Coins hid Red Coins was to grab them, or use a Magnifying Lens. There were twenty Red Coins in each level, and grabbing one added one point to Yoshi's score tally at the end of the level.
They were later seen again in Super Mario 64 and Super Mario 64 DS, in which each one was worth two Gold Coins. Collecting all eight in one course would make a Power Star appear over a Star Marker.
They made another appearance in Super Mario Sunshine. Similar to Super Mario 64, collecting all eight in a level would make a Shine Sprite appear. However, Red Coins did not affect the player's amount of Gold Coins and were treated as a completely different currency.
In New Super Mario Bros., there were Red Rings in most levels, and if the player jumped or swam through one, eight Red Coins would appear. If Mario or Luigi collected them all in the time limit, they were rewarded with a power-up.
Red Coins appeared in Mario Hoops 3 on 3 under the name, 10 Coins. They can be found in ? Panels, and as evident by their name are worth 10 Coins.
In the sequel to Yoshi's Island, Yoshi's Island DS, Red Coins worked the same way as they did in their first appearance; however, the Magnifying Lens was absent in that game.
Red Coins are the most used secondary coins.
