What makes a board retro is any aspect of the board that can be linked to a past era in surfboard design. That being said, ALL surfboards are retro, at least a little. Surfboard design is a progression, building upon the centuries of knowledge that we, as surfers, have accumulated from the Polynesians to Tom Blake to Reynolds Yater to Al Merrick. The “retro” hype is just people getting back into past designs that have been glossed over since the thruster took over the scene. There is lots to learn from going back and tinkering with older designs. I think Matt Moore, Rincon kingpin and world-class shaper in Carpinteria, does some amazing work combining old designs with more modern ideas.