The game uses Green Ronin's "Chronicle System".
Martin's website that Green Ronin Publishing was producing a new line of A Song of Ice and Fire RPG products, unrelated to the earlier Guardians of Order A Game of Thrones effort.
[2][3] Robert J. Schwalb designed the A Song of Ice and Fire Roleplaying game, which was previewed in 2008 and published in 2009; this was his last project for Green Ronin before he moved over to Wizards of the Coast.
[4]: 376 The Green Ronin game, titled A Song of Ice and Fire Roleplaying (SIFRP), went on sale on 10 March 2009: it uses a custom game system and does not contain rules from either the d20 or Tri-Stat dX systems.
A Song of Ice and Fire Roleplaying won the 2009 Silver ENnie Award for Best Rules.