The format rotation is pretty predictable (although subject to alter at WOC discretion).
Cards allowed (in addition to cards that get banned on someone situation basis):
- Cards from 2 latest story-related obstructs
- Cards from any Core set introduced following the older story-related block in standard.
Go back to Ravnica Gatecrash Dragon's Maze secret 2014 Theros Born regarding the Gods Journey Into Nyx (effective May 2, 2014) Magic 2015 Core Set (effective July 28, 2014)
Whenever story-related block is introduced (after secret 2015 primary Set) Return to Ravnica, Gatecrash, Dragon's Maze and secret 2014 will cycle out.
A brand new story-related block and its very first set are usually released every Sept/Oct each year (2 brand new sets associated with block follow after 3-4 months each). Core establishes frequently come out in June/July. Each story-related block is within 'Standard' for approximately a couple of years. Later on units in block and the core establishes frequently cycle call at about a-year.
In 2016, it is planned to change the production routine of new cards and block rotation the standard format. Standard will consist of the last 3 obstructs and each block will rotate on after 18 months.