i would trust masuya, his size advice for my coupen was spot on. in those boots i wear an 8.5 (US) which fits just slightly loose, "perfect" with an insole. i usually wear 10 in vans, 9 converse all stars. my most perfectly sized shoes are a pair of cheaney cairngorms, and strangely i'm also an 8.5 (but UK!, which flies in the face of the usual size down at least half a size from yr US size size advice for shoes/boots) in those. i find the length on the coupen is fairly normal, it's the "volume" of the boots that feels a little oversized. if you have "thin" feet, the boots might feel a bit loose even though the length might be spot on. maybe you can ask masuya how the coupen sizing compares to the caspers.