Final answer:
You may need to upsize in Japanese clothes even if you're 5'1" and have a small frame, as Japanese sizes tend to be smaller. Always check the brand's size chart for proper fitting.
Step-by-step explanation:
When considering whether you need to upsize in Japanese clothes, it's important to note that clothing sizes can vary significantly between different countries. Japanese clothing sizes tend to run smaller when compared to U.S. sizes, so it's likely that if you are 5'1" and have a small body frame, you might still need to consider going one size up when shopping for Japanese clothing. It is always a good idea to check the specific brand's size chart for measurements and to see if they offer international size comparisons to ensure a proper fit.