"The March 2013 Standard arena rotation is now online. On the first Monday of each month, we will be cycling the Standard arena pool. Rather than only having access to the same standard arenas day in and day out, each month we will now feature 24 arenas selected as playable for Standard-level matches.
Newly released arenas will remain exclusive for at least three months, but every other arena is eligible to be included in the cycle."
Standard Map Pool:
Start date: March 4, 2013
End date: April 1, 2013
Duel
TDM
CTF
Beyond Reality
Brimstone Abbey
Cold Cathode
Cold War
Concrete Palace
Corrosion
Devilish
Double Impact
Gothic Rage
Hell's Gate Redux
Heros Keep
Hidden Fortress
IronWorks
Japanese Castles
Nameless Place
Reflux
Sorrow
Stronghold
Terminatria
Tornado
Toxicity
Trinity
Vertical Vengeance
Windsong Keep
Links:
Official announcement
Unharosh.