My husband usually wears a US size 9 which is 270mm in Asian size. Those blue boots are too small. We first ordered a size 9 and found that it was only 260mm long. So we're back and ordering a new size 10 in the same color. To my surprise, we found that the second pair was only marked 265mm. We are now ordering another pair in a size 11 and seeing if they fit my husband's 270mm foot. We don't know other colors for sizing because we don't want to take any more risks due to other factors, so we just ordered the same colors. but i'm sure it's too small for blue. For summer, size 9 is indicated as 260 mm for blue, and size 10 as 265 mm.