AlphaGo defeats Lee Sedol 4–1 at Go
Confirmed
Importance: historic (5 of 5)The takeaway
DeepMind’s AlphaGo beat 18-time world champion Lee Sedol 4–1 in Seoul, a milestone many experts had expected to be a decade away.
Status
- Claim
Confirmed
- Our reporting
- High confidence
- Importance
- Historic (5 of 5)
- Last verified
- 29 September 2026
Your AI and this story
- GPT-6 AstraIn its training data
- Claude Opus 5.5In its training data
- Gemini 4 HydrogenIn its training data
- Grok 4.7In its training data
It happened before the cutoffs of all four assistants, so it can be in their training data.
Key facts
- Match played 9–15 March 2016 in Seoul
- Result: AlphaGo 4, Lee Sedol 1
- Combined deep policy/value networks with Monte Carlo tree search
- Nature paper published 27 January 2016 (after beating Fan Hui 5–0 in Oct 2015)
- Move 37 in game 2 became famous for its creativity
What happened
AlphaGo won the five-game match, with Lee Sedol’s only win coming in game 4.
Why it matters
A watershed for deep reinforcement learning and a ‘Sputnik moment’ that spurred massive AI investment, particularly in China.
Sources
3 sources from 3 sites. Numbers match the chips in the text.
3 sources: 2 primary, 1 reaction
Primary
- Mastering the game of Go with deep neural networks and tree search (Nature, DOI)doi.org, paper
- Google DeepMind: AlphaGodeepmind.google, official
Reactions
- Wikipedia: AlphaGo versus Lee Sedolen.wikipedia.org, discussion
Changes
- Filed