An experiment, originally designed to detect proton decay, carried out with about 300 tonnes of water under Mount Kamioka, Japan. When the experiment was set up in the early 1980s, proton decay was one of the most significant predictions of grand unified theories (GUTs). The experiment’s failure to detect proton decay was a significant negative result, indicating that GUTs in their simplest form are incorrect.

Kamiokande was subsequently modified to Super–Kamiokande (Super–Kamioka Neutrino Detector Experiment), which has provided a lot of useful information about neutrinos.