Non‑linear effects mean that a tiny initial imbalance in a reaction can be amplified, while autocatalysis lets the product help produce more of itself. Together they explain how homochirality – the preference for one mirror‑image form – can arise without external direction.

"Henri Kagan and Kenso Soai have provided a solution to a chemical mystery that is over a century old: how homochirality can emerge spontaneously," said Heiner Linke, chair of the Nobel Committee for Chemistry, adding that the reactions are "spectacular."

The discoveries are decisive for chemists who design reactions for the manufacture of pharmaceuticals, because they allow the selective production of the desired enantiomer, reducing waste and improving efficiency in drug synthesis.

Kagan, 95, is French and works at Université Paris‑Saclay in Orsay, France. Soai, born in 1950 in Japan, conducts his research at the Tokyo University of Science.

The Royal Swedish Academy of Sciences announced the winners in Stockholm, and the laureates will share a prize of 12 million Swedish crowns.

"I’m very excited to receive the very nice news," Soai told the committee and journalists by phone, calling the day one of the most exciting of his life.