Technically, "tied shirt" could simply mean any shirt tied in any manner, including fastened around the waist for hands-free carrying (e.g. post #495578) or even not worn at all. However, for Danbooru purposes, this will usually mean a method of wearing a shirt so that the midriff is exposed. A conventional, buttoned shirt of normal length can be bunched up, and the two loose ends in front tied together, often with the side effect of highlighting the cleavage and/or bustline. A cropped shirt, expressly pre-cut for midriff, may also be used. Another variation involves a T-shirt (post #470358) with one end tied around itself; the knot may appear at the front, side or rear.