The women are leaning and not sitting directly. This time period caused another technological innovation – the fainting couch. Wearing the long, tightly cinching corsets that covered the hips, a woman could not sit straight up in a chair.
Even in loose kimono costume, this photo of Lillie Langtry shows she must have still been wearing a corset (women could not take them off as their organs and ribs had moved in the training of them, and they would move back to natural position and endanger their lives if suddenly they left the corsets off – a key reason for death in child birth).
You can see her leaning on a fainting couch of sorts in this and almost every photo of Langtry during performances. She will be standing or leaning or laying flat; never bent.