Two seats at a display
The Steltman Chair's asymmetry begins to make sense when there are two of them. Rietveld designed a mirrored pair for the interior of Steltman's jewellery shop in The Hague in 1963. Customers could sit beside a display while considering the objects in front of them. The chair was part of that particular arrangement.1
An arm on one side leaves another side open. Reverse the arrangement and the second chair answers the first. The pair establishes a relationship between people, furniture and the display. Mirrored arm placement gives the pair a shared order while each seat remains asymmetric.
Space between the pieces
The exposed-wood version is built from a small vocabulary of upright and horizontal members. Some surfaces support the sitter; others describe a back or an edge. Rectangular gaps are as noticeable as the solid parts. Changing viewpoint changes which of those gaps can be seen through.
Saint Louis Art Museum interprets this balance through Rietveld's return to De Stijl ideas. Its record also preserves an essential practical distinction: Rietveld is the designer, while Gerard van de Groenekan is the maker of the museum's chair.3
The object rewards a slow circuit. From one direction it can look almost closed, from another conspicuously open. The same straight members produce different readings because they occupy different positions in space.

The familiar wood came later
The chairs made for the shop were white-upholstered. Spectrum distinguishes those originals from the exposed-wood version produced after Rietveld's death. The outline that is now often encountered as bare oak therefore has a history involving a different surface.2
That matters to the story because upholstery alters more than colour. It changes the edge, the feel of a surface and the way separate pieces meet the eye. Removing it from the historical account would make today's familiar version appear to be the whole original intention.
A design date is one kind of date
Centraal Museum explicitly labels 1963 as the design date and leaves the execution of its physical example unknown. It can confidently identify the design without pretending that every part of the object's history is settled.1
The same precision makes the story more interesting. There was a commission, an original pair, makers, and later versions. Return to the two seats at the display and the asymmetry stops being merely a striking shape. It becomes a way of arranging an encounter.

