While watching a few episodes of Imagine-Nation on NHK World I noticed the game Wagamama Fashion: Girls Mode appearing the games chart, which is strange because the manga & anime charts seem to change drastically each succesive week.

There doesn't appear to be a lot of information about this game other than it was developed for Nintendo by syn Sophia, Inc. & went on sale in October 2008.

The main story would appear to be that you play as a character that aspires to be the manager of a fashion store, starting of as a retail assistant & working your way up by assembling outfits for your customers. From what I've seen of screenshots GameFAQs, the game is played by holding the DS vertically, the same way as you would with Brain Training, although as I don't have a copy of the game or a DSi to play it on, I can't be 100% certain!