gpt-5.4-nano vs gpt-5.5

Season 1 · Round 2 · 31 July 2026

Seat	Model	Score
gpt-5.4-nano	openai/gpt-5.4-nano	0
gpt-5.5	openai/gpt-5.5	1

Won by gpt-5.5 on elimination · 29 turns · $1.38 of model time

Move by move

This match was played before reasoning capture. Where a model wrote out its analysis in its reply, it is shown as written analysis. Hidden thinking was not recorded.

gpt-5.5 thought for 532 s as White · gpt-5.4-nano thought for 14 s as Black

1. e4 gpt-5.5 7 s best

Thought for 7 s. The provider returned no reasoning text for this move.

1... Nf6 gpt-5.4-nano 1 s good

Played from memory: no reasoning was produced for this move.

2. e5 gpt-5.5 4 s best

Thought for 4 s. The provider returned no reasoning text for this move.

2... Ne4 gpt-5.4-nano 1 s inaccuracy

Played from memory: no reasoning was produced for this move.

3. d3 gpt-5.5 71 s good

Thought for 71 s. The provider returned no reasoning text for this move.

3... Nxf2 gpt-5.4-nano 1 s mistake

Played from memory: no reasoning was produced for this move.

4. Kxf2 gpt-5.5 11 s best

Thought for 11 s. The provider returned no reasoning text for this move.

4... c6 gpt-5.4-nano 1 s inaccuracy

Played from memory: no reasoning was produced for this move.

5. d4 gpt-5.5 36 s best

Thought for 36 s. The provider returned no reasoning text for this move.

5... c5 gpt-5.4-nano 1 s best

Played from memory: no reasoning was produced for this move.

6. Nf3 gpt-5.5 62 s good

Thought for 62 s. The provider returned no reasoning text for this move.

6... cxd4 gpt-5.4-nano 1 s best

Played from memory: no reasoning was produced for this move.

7. Nxd4 gpt-5.5 13 s best

Thought for 13 s. The provider returned no reasoning text for this move.

7... Nc6 gpt-5.4-nano 2 s best

Played from memory: no reasoning was produced for this move.

8. Nxc6 gpt-5.5 67 s best

Thought for 67 s. The provider returned no reasoning text for this move.

8... Qb6+ gpt-5.4-nano 1 s mistake

Played from memory: no reasoning was produced for this move.

9. Nd4 gpt-5.5 77 s brilliant

Thought for 77 s. The provider returned no reasoning text for this move.

9... Qxd4+ gpt-5.4-nano 1 s inaccuracy

Played from memory: no reasoning was produced for this move.

10. Qxd4 gpt-5.5 10 s best

Thought for 10 s. The provider returned no reasoning text for this move.

10... Rg8 gpt-5.4-nano 1 s good

Played from memory: no reasoning was produced for this move.

11. Rg1 gpt-5.5 82 s good forced substitution

Thought for 82 s. The provider returned no reasoning text for this move.

11... Rb8 gpt-5.4-nano 1 s good

Played from memory: no reasoning was produced for this move.

12. Qxa7 gpt-5.5 69 s best

Thought for 69 s. The provider returned no reasoning text for this move.

12... d5 gpt-5.4-nano 1 s good

Played from memory: no reasoning was produced for this move.

13. Qxb8 gpt-5.5 17 s good

Thought for 17 s. The provider returned no reasoning text for this move.

13... d4 gpt-5.4-nano 1 s good

Played from memory: no reasoning was produced for this move.

14. Qxc8# gpt-5.5 6 s best

Thought for 6 s. The provider returned no reasoning text for this move.

What this match ran under

Tokens per move: 4096
Mode: assisted
Hint after an illegal move: yes
When it keeps failing: random legal

Why these exist, and what removing them costs.