Although corsets are common in live-roleplaying, they are discouraged in general in Empire, as they do not fit with the setting. This is because they were little used until the Tudor period, and only in the last 40 years have they been seen as outwear - placing them firmly outside the historical influences for Empire. This page explains more about how we approach corsets in Empire.
The minimum costume standards for Empire state no jeans, t-shirts, or trainers - but as part of the social contract for the game everyone agrees to try and get the best kit possible. To make this possible we need to make clear what look and feel is ideal - and also indicate if items of costume are less appropriate.
In defining this ideal look and feel for Empire we have specifically chosen not to include some images. Some items were omitted so that the overall range of images avoids becoming too broad - we want each nation to look distinctive. Sometimes items were left out because the real world significance of them is so strong that it would impact the game, we want to avoid players confusing these nations with real world cultures. And some items are not part of the ideal because they come from a historical period that isn't part of the inspiration for the game or are too modern in feel.
Corsets are one of the pieces of clothing that is defined as "less appropriate" for Empire - because they don't fit the setting. It is permissible to use these items as part of your character's kit; creating a costume is always a compromise as time and money are limited. What we want to do is be clear on the suggestions we are making, so that players who are looking to create or improve their existing kit can be confident about what would look best for their nation.
Some players may wish to wear a corset underneath their costume, for various reasons. That's acceptable especially if the corset is not visible. In Dawn or the League part of the front could be seen filling the deep 'v' of a gown front (like a plastron). In Navarr a leather corset could be teamed up with a split skirt and rough jacket over the top. In Urizen it might be glimpsed under your robes with a sash around the middle.
Finding good armour that fits the female body is hard. Plate or brigandines made for men are usually too big, are rarely comfortable and almost never flattering. While a leather corset does not meet the rules requirement for armour in Empire - but they can make a good basis for female fitted leather armour. Layer soft leather waistcoats or short cuirass over the top and add tassets or a leather skirt. If worn with mail, the leather corset gives it shape and is very effective at lifting a lot of weight off your shoulders. Underbust designs are best as they allow more movement in the torso.
There are a range of alternatives for costume for players who want something that is figure forming or flattering without using a corset. The list below is not exhaustive, but presents some starting ideas:
A wide leather belt will look great in Wintermark, in other nations you might be able to use a tightly tied sash or a stiffened fabric belt.
Using a stiff lining fabric such as heavy linen or canvas will allow dresses to be laced or buttoned tighter without wrinkling of the fabric or bulging of the bits underneath. The bodice of a dress could also be reinforced by using a flexible plastic boning along the seam lines.
For some nations it may be possible to use corsage within the brief. It is essentially a shaped vest that laces at the back. Historically it was worn over a bliaut (very full dress with long hanging sleeves) and featured frequently in pre-Raphaelite art. It is a simple thing to make and can be reinforced as above in order to lace it tightly over your costume. There is no reason why this couldn't also be used over trousers and shirt in a similar way to a sleeveless doublet, and would therefore work for women who aren't keen on long skirts.
A well fitted dress works wonders for the figure but is difficult to buy off the peg. If you make your own costume, one approach is to leave the side seams open from armpit (potentially up into the upper arm) to hips and lace these closed.