Which format is best for a chess engine tournament: Round-Robin or Swiss?

 For setting up a tournament to watch chess engines compete, let’s break down the Round-Robin and Swiss formats to see which one may be more enjoyable for your goals:

1. Round-Robin Tournament

• Format: Each engine plays every other engine in the tournament. You can configure it as a single round (one game per pairing) or a double round (each pair plays twice, switching colors).
• Advantages:
  • Complete Pairing: Every engine plays against all others, which provides a comprehensive comparison of strength and styles.
  • Fairness: Since each engine plays against all others, it gives a balanced view of their performance.
  • Detailed Results: Round-Robin ensures that you see a full spectrum of engine interactions, revealing which engine is most consistent across various opponents.
• Drawbacks:
  • Time-Consuming: If you have a large pool of engines or are playing multiple rounds, it can take considerable time.
• Best For: Full analysis and enjoyment of every possible matchup. If you’re curious to see how each engine performs against every other engine, Round-Robin is the best choice.

2. Swiss Tournament

• Format: Engines are paired each round based on their performance in previous rounds, with winners facing winners and losers facing losers. However, not every engine plays against all others unless they keep winning or losing at the same rate.
• Advantages:
  • Efficient: Swiss tournaments need fewer rounds than Round-Robin to determine a clear winner, making it faster and more manageable.
  • Competitive Matches: Because it continually pairs engines with similar scores, you’re more likely to see intense, competitive games.
• Drawbacks:
  • Fewer Matchups: Not all engines play each other, so you might miss out on specific pairings, particularly if some engines start winning or losing consistently.
• Best For: Quick comparisons and a focus on top competitors. If you’re looking to determine the strongest engine without watching every possible matchup, Swiss is a good choice.

Which Is Best for Enjoying Chess Engines?

If you want to see how engines perform across different styles and strengths, a Round-Robin tournament is typically the best for enjoyment and analysis. You get to see each engine tackle various approaches, making for a more insightful and entertaining experience.

However, if your priority is efficiency or you have many engines and limited time, the Swiss format can be an engaging alternative that still provides competitive matches and a clear top-performing engine.

For a balanced experience, you might consider a small Round-Robin tournament with just a few games per pairing or a Swiss tournament with more rounds if you're limited on time.