WHY SUDOKU VARIANTS REMAIN A GRAND CHALLENGE IN AI REASONING

Summary from the TLDR AI newsletter

Modified versions of Sudoku test an AI's creativity and ability to strategize around rulesets that don't appear in its training data, unlike fixed-rule games like Chess or Go. GPT-5 is the first LLM to solve a 9x9 variant by simultaneously coordinating four constraint types (standard rules, region sum lines, XV pairs, and Roman numeral cages), but it still only succeeded 20% of the time.