Daihatsu's somewhat ironically named Move is now Japan's most fuel efficient non-hybrid car, clocking 65.5mpg. The formula from making such a fuel efficient vehicle is hardly new, the Move is small, light and has an engine which barely puts out enough power for a sewing machine. Lightweight building practices have been used throughout, and the Move even has a plastic throttle body.
City cars aren't meant to be big, but the Move is small even by those standards, slightly smaller than even the Fiat 500. The 0.66-liter engine is rated at 52hp, which is also pretty low even by the very low standards in this segment. Then engine (such as it is) is bolted to an improved and lightweight CVT. Prices start at about $12,700 and fully loaded, a Move will set you back $18,250. There is even an all-wheel-drive version, which is just hilarious.