One notch, top and bottom.
Look at the top of the back. The rail dips in a wide, shallow notch, with a soft shoulder on each side.
The bottom rail answers it with a tab that drops at the centre. Woven cane fills the shape between them, and the space below stays open.
The arms pick up the same idea. Each one runs back from its post, steps up once and carries on level to the frame.



















