Modern, Legacy, & vintage are constructed formats and therefore adheres to the following constructed rules:

• Minimum of sixty cards
• No maximum deck size, as long as you can shuffle your deck unassisted
• Up to fifteen cards in your sideboard, if used

With the exception of basic lands (Plains, Island, Swamp, Mountain, Forest, and Wastes), your combined deck and sideboard may not contain more than four of any individual card, counted by its English card title equivalent.