Here’s what you need to know about DeepSeek, the Chinese AI startup that rattled markets as its app dethroned OpenAI's as the most-downloaded free app in the U.S. on Apple.

Some AI researchers hailed DeepSeek’s R1 as a breakthrough on the same level as DeepMind’s AlphaZero, a 2017 model that became superhuman at the board games Chess and Go by purely playing against itself and improving, rather than observing any human games.