Wow. Bridgestone / Anchor really blew me away with this. Seriously. Their 10th Anniversay marks the release of the RNC7 Pro, a steel road bike equipped with Dura Ace and beautiful half-lugs.
Their site, although in Japanese seems to say that through re-examining the stresses found in OS tubing, they found that it added uneeded weight and drag. The solution? They made molds by pumping oil to the tube to form the unique shape which enabled them to attach the tubes without lugs. A technique they used on their MTBs back in the ’90s. Really rad. I want one!