Today, this chair is regarded as the supreme icon of modernity. The famous colour scheme of this chair was influenced by its designer’s membership of a modern art movement. His originally designed the chair for his own use in 1918, but he believed that it should be possible to produce it on an industrial scale. The construction of the chair lent itself to mass-production from standard-sized pieces of wood. Its simplicity meant that it could be machined easily using basic tools and assembled by the customer. The chair was initially left in unfinished wood but was coloured in red, blue and yellow in 1923. Rietveld was influenced by De Stijl, a movement that believed art should be based on basic shapes and colours.

'De Stijl' believed in the new design principles that were stressed by Piet Mondrian and Theo van Doesburg's neoplasticism in painting, a clear, geometric ordering of space with roots in Cubism, a "radical renewal of art." Rietveld reasserted the role of furniture as abstract sculpture. He made use of the three primary colors: red, yellow, and blue, using black, white and grey for contrast. Rietveld used new construction techniques with radical shapes and color schemes that have nothing in common with traditional cabinetmaking. His chairs are considered to be among the most exciting three-dimensional works of art created at the time.

Lacquered solid beech wooden "Red blue" armchair - one of the best-known design classics - is made up of a number of different parts that are linked together without the use of any joint. The use of colours throws the different elements into relief and highlights the characteristics of the shape. Lounge chair with frame in black stained beech. Seat (blue) and back (red) in lacquered multiplywood.

The so-called red-blue, the chair made of two boards and a number of laths, that chair was made to the end of showing that a thing of beauty e.g. A spatial object, could be made of nothing but straight, machined materials. So I had the plank sawn into strips and laths; the center part I sawed in two halves, so I had a seat and a back and then, with the laths of various lengths I constructed the chair. When making that thing, it never occurred to me that it would prove to be all that meaningful for myself and possibly for others too; that it would even have an impact on architecture, and when I was given the opportunity of making a house that was based on the very same principles as were incorporated in the chair, I jumped at the occasion, of course."

The construction of the Red/Blue chair is based on a module of 10 cm which correspond approximately to the thickness off three rails and this simple geometric construction is so clear that the chair can be made without using any kind of working drawings. The rails are doweled together and the seat and the back are fixed to the frame with screws.
The subtile mechanical principle of the chair is not so obvious.
Explanation: When a person sits in the chair the seat will transmit his weight to the vertical member which in its turn will transmit the load to the lower horizontal member, but when the load shifts to the chair's back the vertical member will stop and lean in the opposite direction. The movement are based on the side rail which acts like a two-way spring.
So the chair has a mechanical point too.

"The fact that I am constantly concerned with this extraordinary idea of the awakening of consciousness, may account for my work to be inevitably oriented towards spatial problems. Scaling of undefined space to human proportions may be achieved by a line drawn on a road, a floor, a wall, a covering surface, a combination of vertical and horizontal planes, curved or flat, transparent or massive. It is never a partitioning or closing off, but always a defining element of what is here and there, above and below, between and around."

Dyed deal wood and plywood H. 40 x W. 20 1/2 x D. 27 in.

Dutch:
Rood blauwe leunstoel werd één van de bekendste ontwerpen binnen de kunstbeweging De Stijl en is een belangrijk voorbeeld van de vroege modernistische ontwerptechniek, die het "zitten" rationaliseerde en de stoel reduceerde tot een aantal elementaire rechte vormen. Deze stoel, die bestaat uit 15 beukenhouten steunen en twee triplex panelen, toont Rietvelds interesse voor de nieuwe technieken van massaproductie. De houten onderdelen zijn niet verbonden op de conventionele manier, maar met bevestigingen aan de bovenkant of de zijkant. De kleuren, lijnen en vormen doen denken aan het werk van Piet Mondriaan (1872-1944). Ondanks zijn strakke vorm zit deze stoel zelfs zonder kussens erg comfortabel.

Rietveld zelf over zijn Rood-blauwe stoel: "De stoel was speciaal gebouwd om aan te tonen dat het mogelijk is om een mooi object met een ruimtelijke sfeer te ontwerpen dat kan gemaakt worden met eenvoudige machinaal gefabriceerde onderdelen. Ik verzaagde een houten plaat in planken en rechthoeken. Ik deelde het middenste paneel in twee stukken: het zitvlak en de rugsteun en ik maakte het frame uit verschillende lengtes van de plank. Maar ik was wel bezig met een stoel te maken en het kwam nooit bij me op dat dit object zo belangrijk zou worden dat het zelfs de architectuur zou beïnvloeden."