Jack of Harts

Many of those who live on tide-locked Xin Shi never see natural darkness.  Others never see natural light.  They live in the slums, on the edges of the habitable zone, where perpetual freezing night or the blast furnace winds of the sunny side wash over their homes.  It takes a rich person to travel into the prosperous inner zones where day and night meet.  Or a tourist from another world, who is by definition extremely rich on Xin Shi.