And so you know, new core sets come out every year in Summer (July.) Then the Block is (usually) a big release in Fall (September) a small release in Winter (February) and another big set in Spring (May). Sometimes the Big-Small-Big of a block is altered, for example, Dragon's Maze is the small set in RtR, coming third, and Lorowyn-Shadowmoor is more like Big-Small, Big-Small.