Siza partnered with Cauny director Filipe Costa Almeida to design a series that includes four watches with slight variations including strap colour and dial size.
"Designing a wristwatch in dialogue with Filipe Costa Almeida was for me a beautiful and stimulating exercise," said Siza, the 1992 Pritzker Architecture Prize recipient.
"A dialogue in presence, looking at other watches produced by Cauny, made of different choices and an attention to the comments and suggestions over what was right or not."
Almeida said he first met with Siza in May 2021.
"He concluded his first designs in just one month, but then we spent a long time – around 13 months – improving many different prototypes and solving technical problems with the bracelet connection and the dimension of the components until the watch was perfect," said Almeida.
The watches were constructed with a super-slim casing, steel bezel, sapphire glass for the face and a leather bracelet.
The Cauny X Siza series has two different iterations. One is called White and includes a light brown strap and simple single-aspect hands with forked ends.
Mirror, the other iteration, has a black strap and double-aspect hands. Each version comes with either 30 or 35-mm cases and has sans-serif Arabic numerals on the face.
Siza said that when designing the watch, it was important to keep in mind the "millions of new models and continuous changes" that characterise the industry.
"I followed that path with the purpose of making this transformation not imperceptible, and also that this watch would look like a watch, in the same way, that I think a chair should look like a chair and an automobile should look like an automobile," Siza said.
"For what is new need not be an aggression – and that is not always the case."
Siza was involved in the drafting and sketching processes for the watches and worked with Cauny to make sure the watch fit into the brand's style while still reflecting the architect's process.
"Álvaro Siza is perhaps the greatest architect of our time, but also one of the people with whom it was easiest to work," said Almeida.
"In each step of this path, we witnessed the enormous creative vitality, the speed of thought, the freedom in drawing."
Other collaborations between designers and watch brands include Italian design studio Formafantasma's project with Swiss watchmaker Rado.
The portrait photography is by Pedro Ferreira.