The story of what holds the mattress up
For most of furniture history a bed was a frame with rope. Holes were bored through the side rails and a cord was laced across in a grid, and the mattress, a stuffed sack, sat on top of it. The rope stretched constantly, and a bed key was kept in the room to tighten it, which is where the phrase about sleeping tight comes from.
Rope gave way to iron laths, then to wooden slats, and the argument moved to how slats should be arranged. Too far apart and a foam mattress deforms between them. Too close and airflow drops, which matters in humid climates where a mattress needs to breathe from below. Indian workshops settled on solid wood slats at moderate spacing precisely because of the monsoon.
Our artisans still build the platform from solid teak rather than from plywood or engineered board, and still fit a centre rail with its own legs on every bed above queen width. It costs more timber and more labour, and none of it is visible once the mattress is on. It is the part of the bed that decides whether the piece is still comfortable in fifteen years.