Japanese lingerie sizing uses a different convention from European or US sizing, and the difference is significant enough to cause problems if you are not aware of it. At Mind Tech Lab Wave, we size our pieces using our own grading system rather than standard Japanese cup sizing, but understanding the broader context helps when you are comparing across brands.
How Japanese bra sizing works ¶
Japanese bra sizing uses a letter for cup size followed by a number for band size, similar to European sizing but with different band measurements. A Japanese 75B, for example, corresponds to a 34B in US sizing and a 75B in European sizing. The cup increments are the same as European sizing. The main difference is that Japanese sizing tends to run slightly smaller in the band, so if you are between sizes, sizing up in the band is often the right call.
How to take your own measurements ¶
You need two measurements: your underbust (the circumference directly under your bust, measured snugly) and your bust (the circumference at the fullest point of your bust, measured without compression). The difference between the two determines your cup size. A 10cm difference is an A cup, 12.5cm is a B cup, 15cm is a C cup, and so on. Take both measurements without a bra, standing upright, and take each measurement twice to confirm.
How Mind Tech Lab Wave sizes its pieces ¶
We do not use standard Japanese cup sizing. Our pieces are sized XS to XL based on a combination of bust, underbust, and hip measurements. The size guide on our collection page gives the specific measurements for each size. If you are between sizes, our general recommendation is to size up for swimwear and size down for lingerie, but email us with your measurements and we will advise for the specific piece you are considering.
When to consider a bespoke fitting ¶
If you have a significant difference between your underbust and bust measurements, or if your hip and waist measurements fall into different size brackets, a bespoke fitting is worth considering. The appointment takes one hour at our Kyoto atelier. Saya takes twelve measurements and produces a pattern specific to your body. The result is a piece that fits in a way that off-the-shelf sizing cannot replicate.
Sizing is the part of buying lingerie online that most brands handle badly. We try to handle it well. If the size guide does not answer your question, email us directly.