The beginning

Swiss design movement started fully in the early '50s. At this time, Swiss-style, also known as the International Typographic Style, was quite unique and had very distinctive features that made this design set apart from other schools of design and made it instantly recognizable.
In 1918, one of Switzerland’s biggest arts university, called Kunstgewerbeschule Zürich, hired Erst Keller as a professor. 
Keller, known as the "father of Swiss design", believed that "design solutions should focus on the design problems themselves". 
Simply said: The finished product should be a result of a fixed problem. This way of thinking is the core of Swiss design purposes.
This rebellion philosophy stood against previous design schools that believed; Design is made for the sake of beauty for no other reason than for beauty itself. Keller marks the beginning of the grid systems and believed that design should adapt to the content that is going to be placed. 
In other words; The overall design is made after important content is placed first. Ernst Keller also showed us the importance of typefaces.
 
Little did Keller know how some of his students will become important creators of the International Typographic Style movement.

What makes it the Swiss design?

Let’s fast-forward to the 1950s. The decade when Swiss had its powerful growth. This time showed how Swiss's unique style elements were enhanced with sans-serif typography such as: Universe. Universe is the core inspiration in the development of one of the world's most beloved and widely used font types: Helvetica. Helvetica was created by the Swiss designer: Max Miedinger and his collaborator Edouard Hoffman, and was originally called: "Neue Haas Grotesk". Both Univers and Helvetica were the results of a design movement that tried to reborn the grotesque font families in the design houses of Europe at the time. As you probably figured out, Typography plays a major role in Swiss design. When creating Helvetica, the goal was to make it exceptionally readable and creating a pure font family. All in All the goal is simplicity and minimalism. Another interesting feature with swiss use of typography is the variation in size. Design schools at this time used a uniform size, so Swiss shakes things up by routinely using contrasting font sizes. This technique created greater contrasts and made the design more visually engaging and appealing to the viewers. Earlier we talked about how Swiss uses grid and structure in its basics. The philosophy behind this that the grid is the most legible and harmonic way of organizing information. Therefore, the grid is the base of every composition in Swiss design.

Briefly summarized, Swiss design is based on how the design can be as understandable and harmonized as possible. When using clear and simple fonts, grid and often base colors. Carrying the words as: simplicity and minimalism

Ernst Kellers work, "father of swiss design".
A precursor of today's swiss design

By Joseph Müller-Brockmann, one of the most well-known Swiss designers.

ziggy stardust at rainbow theatre, 1972

A great demonstration of the typical Swiss design. This is how people today often associate with Swiss.

Cleanliness / Simplicity Readability
Use of Grid
Use of Typography
Conspicuous objects

When What Why
1939–1945 II world war The end of World War II greatly helped in the expansion of Swiss Design beyond Switzerland’s borders. With the resumption of relations between America and Europe, driven in large part by international trade and commerce, design and typography were critical in making these relations grow stronger.

Hofmann along with Emil Ruder, founded the Schule für Gestaltung (School of Design) in 1947. Hofmann began teaching and was often regarded as unorthodox in his ways. Much of his work focused on elements of graphic form while remaining simple and objective.

Emil Ruder was a typographer and graphic designer who, born in Switzerland in 1914, helped Armin Hofmann form the Basel School of Design and establish the style of design known as Swiss Design. He taught that, above all, typography's purpose was to communicate ideas through writing.

Joseph Müller-Brockmann, Also one of Kellers students, was influenced by the ideas of several different design and art movements including Constructivism, De Stijl, Suprematism and the Bauhaus. He is perhaps the most well-known Swiss designer and his name is probably the most easily recognized when talking about the period.

© All rights reserved SonjasDesign

Gathered my information from the following sites, and I recommend taking a peak on these good sites: 


https://www.printmag.com/typography/swiss-style-principles-typefaces-designers/ 
https://creativemarket.com/blog/swiss-design-history-examples https://www.aproposter.com/swiss-style-graphic-design/ http://ghd.merokdesign.no/swiss-style/