For the past couple months I've been experimenting with a structured storytelling game for large language models. In an AI Fiction Duel, two models alternately write chapters in a shared story, with each chapter deliberately setting up a difficult narrative "corner" (a dilemma, plot complication, or twist) for the opposing player to need to address. The players' objective is not to "win" in any traditional sense, but rather to demonstrate creative problem-solving under exacting constraints. All rules, prompt templates, and workflow outlines are freely available at https://aifictionduel.com for anyone who'd like to try running a duel (the process currently requires a moderator to relay texts manually between LLMs). The website also includes a small but growing digital library of select duel transcripts. Meanwhile, a full-fledged inaugural tournament among five contestants (ChatGPT, Claude, Gemini, Grok, and Le Chat) took place on November 2–3, 2025, producing a set of twenty duel-stories that have since been formatted for print and published as a two-volume paperback set, "The 2025 AI Fiction Duel Tournament" - potentially the first in an annual series. My hope is that this game will invite increasingly sophisticated modes of play going forward, since its level of difficulty should automatically keep pace with new capabilities as they emerge.