Tite Kubo's Bleach has no shortage of breasts, but he chose 10th division lieutenant Rangiku Matsumoto as his flagship mune model. Matsumoto's mounds go unmarred in Japanese print, but it seems that one reader of the US version Shonen Jump noticed some bosom blocking.
While it's no secret that Shonen Jump has to monitor what goes into the US version, it seems that Matsumoto loses a bit of character in translation. Neb's Blog shows a couple of examples of reduction in the Bleach manga, and it looks as if they chose a shirt to cover her excessive cleavage.
The post also includes a picture of the toweling of some bare buttocks and side-boob in the US version, but that makes a bit more sense than the cleavage covering, especially when compared to Robin's equally excessive valley.