# Cross-game model arena — posttrainllm > Inspect provisional Arena Elo for head-to-head games and paired score evidence for single-player games without conflating the two. Canonical: https://posttrainllm.com/benchmarks/arena [Benchmarks](https://posttrainllm.com/benchmarks)/ Game Arena Candidate arena · 2 rating families · 0 hidden conversions # Rate the match. Show the doubt. Head-to-head games earn Arena Elo. Independent games earn paired score evidence. Neither becomes a universal intelligence number. Rating console ## One arena, honest vocabularies. Chess 2048 Competition family **Head-to-head** Rating **Arena Elo** Evidence **4 games · 2 forfeits** 1200 1300 1400 1500 1600 1700 1800 - **Qwen3 4B:** 1585 Arena Elo; unrated. 95% interval: 1500–1733.8. - **Qwen3.5 9B:** 1415 Arena Elo; unrated. 95% interval: 1266.2–1500. The 170-point gap is a regularized diagnostic from four games—not a qualified rank. Two 4B wins came from 9B notation forfeits. This pool-specific Arena Elo is not FIDE, human, engine, Chess.com, or Lichess Elo. Qualification **UNRATED** - Total games **4 / 30** - Per policy **4 / 10** - Forfeit rate **50% / ≤10%** - Color balance **2 white · 2 black** - Connected pool **yes** [Inspect every chess move →](https://posttrainllm.com/benchmarks/chess) Competition family **Independent episodes** Rating **Paired score** Why not Elo **No interacting opponent** −20 −10 0 +10 +20 +30 - **Claude Opus 4.8:** +10.7 paired delta; unqualified. 95% interval: -8–28. - **Claude Sonnet 5:** -1.0 paired delta; unqualified. 95% interval: -14–13. Paired delta compares each model with random legal play on the same seed. The interval crossing zero means no demonstrated advantage. Qualification **UNQUALIFIED** - Claude Opus 4.8: 3 / 30 pairs - Claude Sonnet 5: 4 / 30 pairs - Universal Elo **not applicable** [Inspect every 2048 run →](https://posttrainllm.com/benchmarks/game-2048) Evidence ledger ## A number is the last column, not the first. candidate-only-not-a-public-rating 01 · Match evidence ### Arena Elo Only two interacting policies, win/draw/loss outcomes, one frozen pool, and match-level uncertainty. 02 · Score evidence ### Paired delta Single-player policies share seeds with a baseline. Mean score and uncertainty stay in the game’s own units. 03 · Qualification ### Estimate ≠ rating The math can produce a diagnostic before the sample can support a public rank. We show both states. Extension contract ## Add a game without rewriting the arena. - 1 **Choose a family.** Head-to-head result or independent paired score. - 2 **Normalize evidence.** Participant identity, outcomes, failures, trace hashes, and source paths. - 3 **Freeze qualification.** Sample, balance, connectivity, and failure limits before scoring. - 4 **Reuse the report.** The validator, uncertainty engine, and dashboard remain unchanged. Download arena evidence[Browse benchmark archive](https://posttrainllm.com/benchmarks)